本文将带您了解关于在Docker中进行Redis主从配置的新内容，同时我们还将为您解释docker搭建redis主从的相关知识，另外，我们还将为您提供关于2.docker学习笔记之入门，redis主从
本文将带您了解关于在 Docker 中进行 Redis 主从配置的新内容，同时我们还将为您解释docker搭建redis主从的相关知识，另外，我们还将为您提供关于2.docker 学习笔记之入门，redis 主从配置 1、3.docker学习笔记之入门，redis主从配置2 理论、docker mysql 主从配置、Docker mysql主从配置的实用信息。
本文目录一览：- 在 Docker 中进行 Redis 主从配置（docker搭建redis主从）
- 2.docker 学习笔记之入门，redis 主从配置 1
- 3.docker学习笔记之入门，redis主从配置2 理论
- docker mysql 主从配置
- Docker mysql主从配置
在 Docker 中进行 Redis 主从配置（docker搭建redis主从）
〇、环境准备
1. 两台装好 Docker 的计算机（或两个虚拟机）
我这里是在 VMware 中运行的两个 Centos7 系统
我们把 CentOS-64-0 作为主机（Master），CentOS-64-1 作为从机（Slave）
2. 安装 redis
在 docker 中安装 redis（只把 redis pull 下来，不要进一步配置）
一、在 docker 中使用外部 redis 的配置文件
1. 配置文件 redis.conf
首先在你的两台宿主机上编写好 redis 配置文件，即 redis.conf
可以从 redis 官网下载配置文件模板 在 Centos7 系统中，使用以下命令，下载到本地：
wget http://download.redis.io/redis-stable/redis.conf -O <文件名>
2. 配置参数
主机（Master）修改下载下来的 redis.conf，主要修改参数如下：
#bind 127.0.0.1 #如果bind选项为空的话，则允许所有来自于可用网络接口的连接
protected-mode no #保护模式，若为yes，只允许本地客户端连接
appendonly yes #开启后，Redis会把每次写入的数据在接收后都写入appendonly.aof文件，每次启动时Redis都会先把这个文件的数据读入内存里
从机（Slave）修改下载下来的 redis.conff，主要修改参数如下：
#bind 127.0.0.1
protected-mode no
appendonly yes
# replicaof <master ip> <master port>replicaof 192.168.22.130 6379 #Redis主机(Master)IP 端口
二、在 docker 中创建 redis 容器，并以外部文件启动
1. 主从机器同样启动：
# docker redis 以配置文件运行：
#docker run -p <容器端口>:<主机端口> --name <容器名> -v <本地配置文件映射容器配置文件> -v <本地文件夹挂载到容器文件夹> -d(表示以守护进程方式启动容器) <启动redis服务并制定配置文件(容器中的路径)>
docker run -p 6379:6379 --name myredis -v /usr/local/docker/redis.conf:/usr/local/redis.conf -v /usr/local/docker/data:/usr/local/data -d redis redis-server /usr/local/redis.conf
2. 进入 redis
确保 docker 以及 redis 容器都启动之后，使用 docker exec -it <redis 容器名> redis-cli 命令进入 redis
3. 测试
在主机存入一个 key：
在从机获取：
三、注意
1.replicaof 和 slaveof
在 redis5.x 的主从配置中，从机配置要配置 replicaof 参数。而早期版本，要配置的是 slaveof 参数。
2. 已有 redis 容器
得先删除该容器，待配置好外部 redis.conf 后，重新创建。
3.daemonize 参数
在 docker 中，redis.conf 文件中的 daemonize 参数要设置为 no（默认是 no）。
daemonize=yes 的意思为后台运行 redis，但这会导致容器跑不起来。
4.protected-mode
设置为 yes 时，只允许本地服务端连接，导致不同机子（或虚拟机）的主从机无法连接。
2.docker 学习笔记之入门，redis 主从配置 1
主从复制的作用主要包括：
1、数据冗余：主从复制实现了数据的热备份，是持久化之外的一种数据冗余方式。
2、故障恢复：当主节点出现问题时，可以由从节点提供服务，实现快速的故障恢复；实际上是一种服务的冗余。
3、负载均衡：在主从复制的基础上，配合读写分离，可以由主节点提供写服务，由从节点提供读服务（即写 Redis 数据时应用连接主节点，读 Redis 数据时应用连接从节点）
分担服务器负载；尤其是在写少读多的场景下，通过多个从节点分担读负载，可以大大提高 Redis 服务器的并发量。
4、读写分离：可以用于实现读写分离，主库写、从库读，读写分离不仅可以提高服务器的负载能力，同时可根据需求的变化，改变从库的数量；
5、高可用基石：除了上述作用以外，主从复制还是哨兵和集群能够实施的基础，因此说主从复制是 Redis 高可用的基础。
从节点开启主从复制，有 3 种方式：
（1）配置文件
在从服务器的配置文件中加入：slaveof <masterip> <masterport>
（2）启动命令
redis-server 启动命令后加入 --slaveof <masterip> <masterport>
（3）客户端命令
Redis 服务器启动后，直接通过客户端执行命令：slaveof <masterip> <masterport>，则该 Redis 实例成为从节点。
通过 info replication 命令可以看到复制的一些参数信息
修改配置，把 redis 保护模式关掉了
protected-mode no
准备好 Dockerfile
FROM alpine RUN sed -i ''s/dl-cdn.alpinelinux.org/mirrors.aliyun.com/g'' /etc/apk/repositories \ && apk add gcc g++ libc-dev wget vim openssl-dev make linux-headers \ && rm -rf /var/cache/apk/* #通过选择更小的镜像，删除不必要文件清理不必要的安装缓存，从而瘦身镜像 #创建相关目录能够看到日志信息跟数据跟配置文件 RUN mkdir -p /usr/src/redis \ && mkdir -p /usr/src/redis/data \ && mkdir -p /usr/src/redis/conf \ && mkdir -p /usr/src/redis/log \ && mkdir -p /var/log/redis RUN wget -O /usr/src/redis/redis-4.0.11.tar.gz "http://download.redis.io/releases/redis-4.0.11.tar.gz" \ && tar -xzf /usr/src/redis/redis-4.0.11.tar.gz -C /usr/src/redis \ && rm -rf /usr/src/redis/redis-4.0.11.tar.tgz RUN cd /usr/src/redis/redis-4.0.11 && make && make PREFIX=/usr/local/redis install \ && ln -s /usr/local/redis/bin/* /usr/local/bin/ && rm -rf /usr/src/redis/redis-4.0.11 #COPY ./conf/redis.conf /usr/src/redis/conf CMD ["/usr/local/bin/redis-server","/usr/src/redis/conf/redis.conf"]
构建镜像
准备 redis 主节点的配置文件
# Redis configuration file example. # # Note that in order to read the configuration file, Redis must be # started with the file path as first argument: # # ./redis-server /path/to/redis.conf # Note on units: when memory size is needed, it is possible to specify # it in the usual form of 1k 5GB 4M and so forth: # # 1k => 1000 bytes # 1kb => 1024 bytes # 1m => 1000000 bytes # 1mb => 1024*1024 bytes # 1g => 1000000000 bytes # 1gb => 1024*1024*1024 bytes # # units are case insensitive so 1GB 1Gb 1gB are all the same. ################################## INCLUDES ################################### # Include one or more other config files here. This is useful if you # have a standard template that goes to all Redis servers but also need # to customize a few per-server settings. Include files can include # other files, so use this wisely. # # Notice option "include" won''t be rewritten by command "CONFIG REWRITE" # from admin or Redis Sentinel. Since Redis always uses the last processed # line as value of a configuration directive, you''d better put includes # at the beginning of this file to avoid overwriting config change at runtime. # # If instead you are interested in using includes to override configuration # options, it is better to use include as the last line. # # include /path/to/local.conf # include /path/to/other.conf ################################## NETWORK ##################################### # By default, if no "bind" configuration directive is specified, Redis listens # for connections from all the network interfaces available on the server. # It is possible to listen to just one or multiple selected interfaces using # the "bind" configuration directive, followed by one or more IP addresses. # # Examples: # # bind 192.168.1.100 10.0.0.1 # bind 127.0.0.1 ::1 # # ~~~ WARNING ~~~ If the computer running Redis is directly exposed to the # internet, binding to all the interfaces is dangerous and will expose the # instance to everybody on the internet. So by default we uncomment the # following bind directive, that will force Redis to listen only into # the IPv4 lookback interface address (this means Redis will be able to # accept connections only from clients running into the same computer it # is running). # # IF YOU ARE SURE YOU WANT YOUR INSTANCE TO LISTEN TO ALL THE INTERFACES # JUST COMMENT THE FOLLOWING LINE. # ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ bind 0.0.0.0 # Protected mode is a layer of security protection, in order to avoid that # Redis instances left open on the internet are accessed and exploited. # # When protected mode is on and if: # # 1) The server is not binding explicitly to a set of addresses using the # "bind" directive. # 2) No password is configured. # # The server only accepts connections from clients connecting from the # IPv4 and IPv6 loopback addresses 127.0.0.1 and ::1, and from Unix domain # sockets. # # By default protected mode is enabled. You should disable it only if # you are sure you want clients from other hosts to connect to Redis # even if no authentication is configured, nor a specific set of interfaces # are explicitly listed using the "bind" directive. protected-mode no # Accept connections on the specified port, default is 6379 (IANA #815344). # If port 0 is specified Redis will not listen on a TCP socket. port 6379 # TCP listen() backlog. # # In high requests-per-second environments you need an high backlog in order # to avoid slow clients connections issues. Note that the Linux kernel # will silently truncate it to the value of /proc/sys/net/core/somaxconn so # make sure to raise both the value of somaxconn and tcp_max_syn_backlog # in order to get the desired effect. #用于保存未连接的tcp请求队列 tcp-backlog 511 # Unix socket. # # Specify the path for the Unix socket that will be used to listen for # incoming connections. There is no default, so Redis will not listen # on a unix socket when not specified. # # unixsocket /tmp/redis.sock # unixsocketperm 700 # Close the connection after a client is idle for N seconds (0 to disable) timeout 0 # TCP keepalive. # # If non-zero, use SO_KEEPALIVE to send TCP ACKs to clients in absence # of communication. This is useful for two reasons: # # 1) Detect dead peers. # 2) Take the connection alive from the point of view of network # equipment in the middle. # # On Linux, the specified value (in seconds) is the period used to send ACKs. # Note that to close the connection the double of the time is needed. # On other kernels the period depends on the kernel configuration. # # A reasonable value for this option is 300 seconds, which is the new # Redis default starting with Redis 3.2.1. tcp-keepalive 300 ################################# GENERAL ##################################### # By default Redis does not run as a daemon. Use ''yes'' if you need it. # Note that Redis will write a pid file in /var/run/redis.pid when daemonized. daemonize no # If you run Redis from upstart or systemd, Redis can interact with your # supervision tree. Options: # supervised no - no supervision interaction # supervised upstart - signal upstart by putting Redis into SIGSTOP mode # supervised systemd - signal systemd by writing READY=1 to $NOTIFY_SOCKET # supervised auto - detect upstart or systemd method based on # UPSTART_JOB or NOTIFY_SOCKET environment variables # Note: these supervision methods only signal "process is ready." # They do not enable continuous liveness pings back to your supervisor. supervised no # If a pid file is specified, Redis writes it where specified at startup # and removes it at exit. # # When the server runs non daemonized, no pid file is created if none is # specified in the configuration. When the server is daemonized, the pid file # is used even if not specified, defaulting to "/var/run/redis.pid". # # Creating a pid file is best effort: if Redis is not able to create it # nothing bad happens, the server will start and run normally. pidfile "/var/run/redis_6379.pid" # Specify the server verbosity level. # This can be one of: # debug (a lot of information, useful for development/testing) # verbose (many rarely useful info, but not a mess like the debug level) # notice (moderately verbose, what you want in production probably) # warning (only very important / critical messages are logged) loglevel notice # Specify the log file name. Also the empty string can be used to force # Redis to log on the standard output. Note that if you use standard # output for logging but daemonize, logs will be sent to /dev/null logfile "/usr/src/redis/log/redis.log" # To enable logging to the system logger, just set ''syslog-enabled'' to yes, # and optionally update the other syslog parameters to suit your needs. # syslog-enabled no # Specify the syslog identity. # syslog-ident redis # Specify the syslog facility. Must be USER or between LOCAL0-LOCAL7. # syslog-facility local0 # Set the number of databases. The default database is DB 0, you can select # a different one on a per-connection basis using SELECT <dbid> where # dbid is a number between 0 and ''databases''-1 databases 16 ################################ SNAPSHOTTING ################################ # # Save the DB on disk: # # save <seconds> <changes> # # Will save the DB if both the given number of seconds and the given # number of write operations against the DB occurred. # # In the example below the behaviour will be to save: # after 900 sec (15 min) if at least 1 key changed # after 300 sec (5 min) if at least 10 keys changed # after 60 sec if at least 10000 keys changed # # Note: you can disable saving completely by commenting out all "save" lines. # # It is also possible to remove all the previously configured save # points by adding a save directive with a single empty string argument # like in the following example: # # save "" #持久化规则 save 900 1 save 300 10 save 60 10000 # By default Redis will stop accepting writes if RDB snapshots are enabled # (at least one save point) and the latest background save failed. # This will make the user aware (in a hard way) that data is not persisting # on disk properly, otherwise chances are that no one will notice and some # disaster will happen. # # If the background saving process will start working again Redis will # automatically allow writes again. # # However if you have setup your proper monitoring of the Redis server # and persistence, you may want to disable this feature so that Redis will # continue to work as usual even if there are problems with disk, # permissions, and so forth. stop-writes-on-bgsave-error yes # Compress string objects using LZF when dump .rdb databases? # For default that''s set to ''yes'' as it''s almost always a win. # If you want to save some CPU in the saving child set it to ''no'' but # the dataset will likely be bigger if you have compressible values or keys. rdbcompression yes # Since version 5 of RDB a CRC64 checksum is placed at the end of the file. # This makes the format more resistant to corruption but there is a performance # hit to pay (around 10%) when saving and loading RDB files, so you can disable it # for maximum performances. # # RDB files created with checksum disabled have a checksum of zero that will # tell the loading code to skip the check. rdbchecksum yes # The filename where to dump the DB dbfilename "dump.rdb" # The working directory. # # The DB will be written inside this directory, with the filename specified # above using the ''dbfilename'' configuration directive. # # The Append Only File will also be created inside this directory. # # Note that you must specify a directory here, not a file name. dir "/usr/src/redis/data" ################################# REPLICATION ################################# # Master-Slave replication. Use slaveof to make a Redis instance a copy of # another Redis server. A few things to understand ASAP about Redis replication. # # 1) Redis replication is asynchronous, but you can configure a master to # stop accepting writes if it appears to be not connected with at least # a given number of slaves. # 2) Redis slaves are able to perform a partial resynchronization with the # master if the replication link is lost for a relatively small amount of # time. You may want to configure the replication backlog size (see the next # sections of this file) with a sensible value depending on your needs. # 3) Replication is automatic and does not need user intervention. After a # network partition slaves automatically try to reconnect to masters # and resynchronize with them. # # slaveof <masterip> <masterport> # If the master is password protected (using the "requirepass" configuration # directive below) it is possible to tell the slave to authenticate before # starting the replication synchronization process, otherwise the master will # refuse the slave request. # # masterauth <master-password> # When a slave loses its connection with the master, or when the replication # is still in progress, the slave can act in two different ways: # # 1) if slave-serve-stale-data is set to ''yes'' (the default) the slave will # still reply to client requests, possibly with out of date data, or the # data set may just be empty if this is the first synchronization. # # 2) if slave-serve-stale-data is set to ''no'' the slave will reply with # an error "SYNC with master in progress" to all the kind of commands # but to INFO and SLAVEOF. # slave-serve-stale-data yes # You can configure a slave instance to accept writes or not. Writing against # a slave instance may be useful to store some ephemeral data (because data # written on a slave will be easily deleted after resync with the master) but # may also cause problems if clients are writing to it because of a # misconfiguration. # # Since Redis 2.6 by default slaves are read-only. # # Note: read only slaves are not designed to be exposed to untrusted clients # on the internet. It''s just a protection layer against misuse of the instance. # Still a read only slave exports by default all the administrative commands # such as CONFIG, DEBUG, and so forth. To a limited extent you can improve # security of read only slaves using ''rename-command'' to shadow all the # administrative / dangerous commands. slave-read-only yes # Replication SYNC strategy: disk or socket. # # ------------------------------------------------------- # WARNING: DISKLESS REPLICATION IS EXPERIMENTAL CURRENTLY # ------------------------------------------------------- # # New slaves and reconnecting slaves that are not able to continue the replication # process just receiving differences, need to do what is called a "full # synchronization". An RDB file is transmitted from the master to the slaves. # The transmission can happen in two different ways: # # 1) Disk-backed: The Redis master creates a new process that writes the RDB # file on disk. Later the file is transferred by the parent # process to the slaves incrementally. # 2) Diskless: The Redis master creates a new process that directly writes the # RDB file to slave sockets, without touching the disk at all. # # With disk-backed replication, while the RDB file is generated, more slaves # can be queued and served with the RDB file as soon as the current child producing # the RDB file finishes its work. With diskless replication instead once # the transfer starts, new slaves arriving will be queued and a new transfer # will start when the current one terminates. # # When diskless replication is used, the master waits a configurable amount of # time (in seconds) before starting the transfer in the hope that multiple slaves # will arrive and the transfer can be parallelized. # # With slow disks and fast (large bandwidth) networks, diskless replication # works better. repl-diskless-sync no # When diskless replication is enabled, it is possible to configure the delay # the server waits in order to spawn the child that transfers the RDB via socket # to the slaves. # # This is important since once the transfer starts, it is not possible to serve # new slaves arriving, that will be queued for the next RDB transfer, so the server # waits a delay in order to let more slaves arrive. # # The delay is specified in seconds, and by default is 5 seconds. To disable # it entirely just set it to 0 seconds and the transfer will start ASAP. repl-diskless-sync-delay 5 # Slaves send PINGs to server in a predefined interval. It''s possible to change # this interval with the repl_ping_slave_period option. The default value is 10 # seconds. # # repl-ping-slave-period 10 # The following option sets the replication timeout for: # # 1) Bulk transfer I/O during SYNC, from the point of view of slave. # 2) Master timeout from the point of view of slaves (data, pings). # 3) Slave timeout from the point of view of masters (REPLCONF ACK pings). # # It is important to make sure that this value is greater than the value # specified for repl-ping-slave-period otherwise a timeout will be detected # every time there is low traffic between the master and the slave. # # repl-timeout 60 # Disable TCP_NODELAY on the slave socket after SYNC? # # If you select "yes" Redis will use a smaller number of TCP packets and # less bandwidth to send data to slaves. But this can add a delay for # the data to appear on the slave side, up to 40 milliseconds with # Linux kernels using a default configuration. # # If you select "no" the delay for data to appear on the slave side will # be reduced but more bandwidth will be used for replication. # # By default we optimize for low latency, but in very high traffic conditions # or when the master and slaves are many hops away, turning this to "yes" may # be a good idea. repl-disable-tcp-nodelay no # Set the replication backlog size. The backlog is a buffer that accumulates # slave data when slaves are disconnected for some time, so that when a slave # wants to reconnect again, often a full resync is not needed, but a partial # resync is enough, just passing the portion of data the slave missed while # disconnected. # # The bigger the replication backlog, the longer the time the slave can be # disconnected and later be able to perform a partial resynchronization. # # The backlog is only allocated once there is at least a slave connected. # # repl-backlog-size 1mb # After a master has no longer connected slaves for some time, the backlog # will be freed. The following option configures the amount of seconds that # need to elapse, starting from the time the last slave disconnected, for # the backlog buffer to be freed. # # A value of 0 means to never release the backlog. # # repl-backlog-ttl 3600 # The slave priority is an integer number published by Redis in the INFO output. # It is used by Redis Sentinel in order to select a slave to promote into a # master if the master is no longer working correctly. # # A slave with a low priority number is considered better for promotion, so # for instance if there are three slaves with priority 10, 100, 25 Sentinel will # pick the one with priority 10, that is the lowest. # # However a special priority of 0 marks the slave as not able to perform the # role of master, so a slave with priority of 0 will never be selected by # Redis Sentinel for promotion. # # By default the priority is 100. slave-priority 100 # It is possible for a master to stop accepting writes if there are less than # N slaves connected, having a lag less or equal than M seconds. # # The N slaves need to be in "online" state. # # The lag in seconds, that must be <= the specified value, is calculated from # the last ping received from the slave, that is usually sent every second. # # This option does not GUARANTEE that N replicas will accept the write, but # will limit the window of exposure for lost writes in case not enough slaves # are available, to the specified number of seconds. # # For example to require at least 3 slaves with a lag <= 10 seconds use: # # min-slaves-to-write 3 # min-slaves-max-lag 10 # # Setting one or the other to 0 disables the feature. # # By default min-slaves-to-write is set to 0 (feature disabled) and # min-slaves-max-lag is set to 10. # A Redis master is able to list the address and port of the attached # slaves in different ways. For example the "INFO replication" section # offers this information, which is used, among other tools, by # Redis Sentinel in order to discover slave instances. # Another place where this info is available is in the output of the # "ROLE" command of a masteer. # # The listed IP and address normally reported by a slave is obtained # in the following way: # # IP: The address is auto detected by checking the peer address # of the socket used by the slave to connect with the master. # # Port: The port is communicated by the slave during the replication # handshake, and is normally the port that the slave is using to # list for connections. # # However when port forwarding or Network Address Translation (NAT) is # used, the slave may be actually reachable via different IP and port # pairs. The following two options can be used by a slave in order to # report to its master a specific set of IP and port, so that both INFO # and ROLE will report those values. # # There is no need to use both the options if you need to override just # the port or the IP address. # # slave-announce-ip 5.5.5.5 # slave-announce-port 1234 ################################## SECURITY ################################### # Require clients to issue AUTH <PASSWORD> before processing any other # commands. This might be useful in environments in which you do not trust # others with access to the host running redis-server. # # This should stay commented out for backward compatibility and because most # people do not need auth (e.g. they run their own servers). # # Warning: since Redis is pretty fast an outside user can try up to # 150k passwords per second against a good box. This means that you should # use a very strong password otherwise it will be very easy to break. # requirepass 123456 # Command renaming. # # It is possible to change the name of dangerous commands in a shared # environment. For instance the CONFIG command may be renamed into something # hard to guess so that it will still be available for internal-use tools # but not available for general clients. # # Example: # # rename-command CONFIG b840fc02d524045429941cc15f59e41cb7be6c52 # # It is also possible to completely kill a command by renaming it into # an empty string: # # rename-command CONFIG "" # # Please note that changing the name of commands that are logged into the # AOF file or transmitted to slaves may cause problems. ################################### LIMITS #################################### # Set the max number of connected clients at the same time. By default # this limit is set to 10000 clients, however if the Redis server is not # able to configure the process file limit to allow for the specified limit # the max number of allowed clients is set to the current file limit # minus 32 (as Redis reserves a few file descriptors for internal uses). # # Once the limit is reached Redis will close all the new connections sending # an error ''max number of clients reached''. # # maxclients 10000 # Don''t use more memory than the specified amount of bytes. # When the memory limit is reached Redis will try to remove keys # according to the eviction policy selected (see maxmemory-policy). # # If Redis can''t remove keys according to the policy, or if the policy is # set to ''noeviction'', Redis will start to reply with errors to commands # that would use more memory, like SET, LPUSH, and so on, and will continue # to reply to read-only commands like GET. # # This option is usually useful when using Redis as an LRU cache, or to set # a hard memory limit for an instance (using the ''noeviction'' policy). # # WARNING: If you have slaves attached to an instance with maxmemory on, # the size of the output buffers needed to feed the slaves are subtracted # from the used memory count, so that network problems / resyncs will # not trigger a loop where keys are evicted, and in turn the output # buffer of slaves is full with DELs of keys evicted triggering the deletion # of more keys, and so forth until the database is completely emptied. # # In short... if you have slaves attached it is suggested that you set a lower # limit for maxmemory so that there is some free RAM on the system for slave # output buffers (but this is not needed if the policy is ''noeviction''). # # maxmemory <bytes> # MAXMEMORY POLICY: how Redis will select what to remove when maxmemory # is reached. You can select among five behaviors: # # volatile-lru -> remove the key with an expire set using an LRU algorithm # allkeys-lru -> remove any key according to the LRU algorithm # volatile-random -> remove a random key with an expire set # allkeys-random -> remove a random key, any key # volatile-ttl -> remove the key with the nearest expire time (minor TTL) # noeviction -> don''t expire at all, just return an error on write operations # # Note: with any of the above policies, Redis will return an error on write # operations, when there are no suitable keys for eviction. # # At the date of writing these commands are: set setnx setex append # incr decr rpush lpush rpushx lpushx linsert lset rpoplpush sadd # sinter sinterstore sunion sunionstore sdiff sdiffstore zadd zincrby # zunionstore zinterstore hset hsetnx hmset hincrby incrby decrby # getset mset msetnx exec sort # # The default is: # # maxmemory-policy noeviction # LRU and minimal TTL algorithms are not precise algorithms but approximated # algorithms (in order to save memory), so you can tune it for speed or # accuracy. For default Redis will check five keys and pick the one that was # used less recently, you can change the sample size using the following # configuration directive. # # The default of 5 produces good enough results. 10 Approximates very closely # true LRU but costs a bit more CPU. 3 is very fast but not very accurate. # # maxmemory-samples 5 ############################## APPEND ONLY MODE ############################### # By default Redis asynchronously dumps the dataset on disk. This mode is # good enough in many applications, but an issue with the Redis process or # a power outage may result into a few minutes of writes lost (depending on # the configured save points). # # The Append Only File is an alternative persistence mode that provides # much better durability. For instance using the default data fsync policy # (see later in the config file) Redis can lose just one second of writes in a # dramatic event like a server power outage, or a single write if something # wrong with the Redis process itself happens, but the operating system is # still running correctly. # # AOF and RDB persistence can be enabled at the same time without problems. # If the AOF is enabled on startup Redis will load the AOF, that is the file # with the better durability guarantees. # # Please check http://redis.io/topics/persistence for more information. appendonly no # The name of the append only file (default: "appendonly.aof") appendfilename "appendonly.aof" # The fsync() call tells the Operating System to actually write data on disk # instead of waiting for more data in the output buffer. Some OS will really flush # data on disk, some other OS will just try to do it ASAP. # # Redis supports three different modes: # # no: don''t fsync, just let the OS flush the data when it wants. Faster. # always: fsync after every write to the append only log. Slow, Safest. # everysec: fsync only one time every second. Compromise. # # The default is "everysec", as that''s usually the right compromise between # speed and data safety. It''s up to you to understand if you can relax this to # "no" that will let the operating system flush the output buffer when # it wants, for better performances (but if you can live with the idea of # some data loss consider the default persistence mode that''s snapshotting), # or on the contrary, use "always" that''s very slow but a bit safer than # everysec. # # More details please check the following article: # http://antirez.com/post/redis-persistence-demystified.html # # If unsure, use "everysec". # appendfsync always appendfsync everysec # appendfsync no # When the AOF fsync policy is set to always or everysec, and a background # saving process (a background save or AOF log background rewriting) is # performing a lot of I/O against the disk, in some Linux configurations # Redis may block too long on the fsync() call. Note that there is no fix for # this currently, as even performing fsync in a different thread will block # our synchronous write(2) call. # # In order to mitigate this problem it''s possible to use the following option # that will prevent fsync() from being called in the main process while a # BGSAVE or BGREWRITEAOF is in progress. # # This means that while another child is saving, the durability of Redis is # the same as "appendfsync none". In practical terms, this means that it is # possible to lose up to 30 seconds of log in the worst scenario (with the # default Linux settings). # # If you have latency problems turn this to "yes". Otherwise leave it as # "no" that is the safest pick from the point of view of durability. no-appendfsync-on-rewrite no # Automatic rewrite of the append only file. # Redis is able to automatically rewrite the log file implicitly calling # BGREWRITEAOF when the AOF log size grows by the specified percentage. # # This is how it works: Redis remembers the size of the AOF file after the # latest rewrite (if no rewrite has happened since the restart, the size of # the AOF at startup is used). # # This base size is compared to the current size. If the current size is # bigger than the specified percentage, the rewrite is triggered. Also # you need to specify a minimal size for the AOF file to be rewritten, this # is useful to avoid rewriting the AOF file even if the percentage increase # is reached but it is still pretty small. # # Specify a percentage of zero in order to disable the automatic AOF # rewrite feature. auto-aof-rewrite-percentage 100 auto-aof-rewrite-min-size 64mb # An AOF file may be found to be truncated at the end during the Redis # startup process, when the AOF data gets loaded back into memory. # This may happen when the system where Redis is running # crashes, especially when an ext4 filesystem is mounted without the # data=ordered option (however this can''t happen when Redis itself # crashes or aborts but the operating system still works correctly). # # Redis can either exit with an error when this happens, or load as much # data as possible (the default now) and start if the AOF file is found # to be truncated at the end. The following option controls this behavior. # # If aof-load-truncated is set to yes, a truncated AOF file is loaded and # the Redis server starts emitting a log to inform the user of the event. # Otherwise if the option is set to no, the server aborts with an error # and refuses to start. When the option is set to no, the user requires # to fix the AOF file using the "redis-check-aof" utility before to restart # the server. # # Note that if the AOF file will be found to be corrupted in the middle # the server will still exit with an error. This option only applies when # Redis will try to read more data from the AOF file but not enough bytes # will be found. aof-load-truncated yes ################################ LUA SCRIPTING ############################### # Max execution time of a Lua script in milliseconds. # # If the maximum execution time is reached Redis will log that a script is # still in execution after the maximum allowed time and will start to # reply to queries with an error. # # When a long running script exceeds the maximum execution time only the # SCRIPT KILL and SHUTDOWN NOSAVE commands are available. The first can be # used to stop a script that did not yet called write commands. The second # is the only way to shut down the server in the case a write command was # already issued by the script but the user doesn''t want to wait for the natural # termination of the script. # # Set it to 0 or a negative value for unlimited execution without warnings. lua-time-limit 5000 ################################ REDIS CLUSTER ############################### # # ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ # WARNING EXPERIMENTAL: Redis Cluster is considered to be stable code, however # in order to mark it as "mature" we need to wait for a non trivial percentage # of users to deploy it in production. # ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ # # Normal Redis instances can''t be part of a Redis Cluster; only nodes that are # started as cluster nodes can. In order to start a Redis instance as a # cluster node enable the cluster support uncommenting the following: # cluster-enabled no # Every cluster node has a cluster configuration file. This file is not # intended to be edited by hand. It is created and updated by Redis nodes. # Every Redis Cluster node requires a different cluster configuration file. # Make sure that instances running in the same system do not have # overlapping cluster configuration file names. # cluster-config-file nodes-6379.conf # Cluster node timeout is the amount of milliseconds a node must be unreachable # for it to be considered in failure state. # Most other internal time limits are multiple of the node timeout. # cluster-node-timeout 15000 # A slave of a failing master will avoid to start a failover if its data # looks too old. # # There is no simple way for a slave to actually have a exact measure of # its "data age", so the following two checks are performed: # # 1) If there are multiple slaves able to failover, they exchange messages # in order to try to give an advantage to the slave with the best # replication offset (more data from the master processed). # Slaves will try to get their rank by offset, and apply to the start # of the failover a delay proportional to their rank. # # 2) Every single slave computes the time of the last interaction with # its master. This can be the last ping or command received (if the master # is still in the "connected" state), or the time that elapsed since the # disconnection with the master (if the replication link is currently down). # If the last interaction is too old, the slave will not try to failover # at all. # # The point "2" can be tuned by user. Specifically a slave will not perform # the failover if, since the last interaction with the master, the time # elapsed is greater than: # # (node-timeout * slave-validity-factor) + repl-ping-slave-period # # So for example if node-timeout is 30 seconds, and the slave-validity-factor # is 10, and assuming a default repl-ping-slave-period of 10 seconds, the # slave will not try to failover if it was not able to talk with the master # for longer than 310 seconds. # # A large slave-validity-factor may allow slaves with too old data to failover # a master, while a too small value may prevent the cluster from being able to # elect a slave at all. # # For maximum availability, it is possible to set the slave-validity-factor # to a value of 0, which means, that slaves will always try to failover the # master regardless of the last time they interacted with the master. # (However they''ll always try to apply a delay proportional to their # offset rank). # # Zero is the only value able to guarantee that when all the partitions heal # the cluster will always be able to continue. # # cluster-slave-validity-factor 10 # Cluster slaves are able to migrate to orphaned masters, that are masters # that are left without working slaves. This improves the cluster ability # to resist to failures as otherwise an orphaned master can''t be failed over # in case of failure if it has no working slaves. # # Slaves migrate to orphaned masters only if there are still at least a # given number of other working slaves for their old master. This number # is the "migration barrier". A migration barrier of 1 means that a slave # will migrate only if there is at least 1 other working slave for its master # and so forth. It usually reflects the number of slaves you want for every # master in your cluster. # # Default is 1 (slaves migrate only if their masters remain with at least # one slave). To disable migration just set it to a very large value. # A value of 0 can be set but is useful only for debugging and dangerous # in production. # # cluster-migration-barrier 1 # By default Redis Cluster nodes stop accepting queries if they detect there # is at least an hash slot uncovered (no available node is serving it). # This way if the cluster is partially down (for example a range of hash slots # are no longer covered) all the cluster becomes, eventually, unavailable. # It automatically returns available as soon as all the slots are covered again. # # However sometimes you want the subset of the cluster which is working, # to continue to accept queries for the part of the key space that is still # covered. In order to do so, just set the cluster-require-full-coverage # option to no. # # cluster-require-full-coverage yes # In order to setup your cluster make sure to read the documentation # available at http://redis.io web site. ################################## SLOW LOG ################################### # The Redis Slow Log is a system to log queries that exceeded a specified # execution time. The execution time does not include the I/O operations # like talking with the client, sending the reply and so forth, # but just the time needed to actually execute the command (this is the only # stage of command execution where the thread is blocked and can not serve # other requests in the meantime). # # You can configure the slow log with two parameters: one tells Redis # what is the execution time, in microseconds, to exceed in order for the # command to get logged, and the other parameter is the length of the # slow log. When a new command is logged the oldest one is removed from the # queue of logged commands. # The following time is expressed in microseconds, so 1000000 is equivalent # to one second. Note that a negative number disables the slow log, while # a value of zero forces the logging of every command. slowlog-log-slower-than 10000 # There is no limit to this length. Just be aware that it will consume memory. # You can reclaim memory used by the slow log with SLOWLOG RESET. slowlog-max-len 128 ################################ LATENCY MONITOR ############################## # The Redis latency monitoring subsystem samples different operations # at runtime in order to collect data related to possible sources of # latency of a Redis instance. # # Via the LATENCY command this information is available to the user that can # print graphs and obtain reports. # # The system only logs operations that were performed in a time equal or # greater than the amount of milliseconds specified via the # latency-monitor-threshold configuration directive. When its value is set # to zero, the latency monitor is turned off. # # By default latency monitoring is disabled since it is mostly not needed # if you don''t have latency issues, and collecting data has a performance # impact, that while very small, can be measured under big load. Latency # monitoring can easily be enabled at runtime using the command # "CONFIG SET latency-monitor-threshold <milliseconds>" if needed. latency-monitor-threshold 0 ############################# EVENT NOTIFICATION ############################## # Redis can notify Pub/Sub clients about events happening in the key space. # This feature is documented at http://redis.io/topics/notifications # # For instance if keyspace events notification is enabled, and a client # performs a DEL operation on key "foo" stored in the Database 0, two # messages will be published via Pub/Sub: # # PUBLISH __keyspace@0__:foo del # PUBLISH __keyevent@0__:del foo # # It is possible to select the events that Redis will notify among a set # of classes. Every class is identified by a single character: # # K Keyspace events, published with __keyspace@<db>__ prefix. # E Keyevent events, published with __keyevent@<db>__ prefix. # g Generic commands (non-type specific) like DEL, EXPIRE, RENAME, ... # $ String commands # l List commands # s Set commands # h Hash commands # z Sorted set commands # x Expired events (events generated every time a key expires) # e Evicted events (events generated when a key is evicted for maxmemory) # A Alias for g$lshzxe, so that the "AKE" string means all the events. # # The "notify-keyspace-events" takes as argument a string that is composed # of zero or multiple characters. The empty string means that notifications # are disabled. # # Example: to enable list and generic events, from the point of view of the # event name, use: # # notify-keyspace-events Elg # # Example 2: to get the stream of the expired keys subscribing to channel # name __keyevent@0__:expired use: # # notify-keyspace-events Ex # # By default all notifications are disabled because most users don''t need # this feature and the feature has some overhead. Note that if you don''t # specify at least one of K or E, no events will be delivered. notify-keyspace-events "" ############################### ADVANCED CONFIG ############################### # Hashes are encoded using a memory efficient data structure when they have a # small number of entries, and the biggest entry does not exceed a given # threshold. These thresholds can be configured using the following directives. hash-max-ziplist-entries 512 hash-max-ziplist-value 64 # Lists are also encoded in a special way to save a lot of space. # The number of entries allowed per internal list node can be specified # as a fixed maximum size or a maximum number of elements. # For a fixed maximum size, use -5 through -1, meaning: # -5: max size: 64 Kb <-- not recommended for normal workloads # -4: max size: 32 Kb <-- not recommended # -3: max size: 16 Kb <-- probably not recommended # -2: max size: 8 Kb <-- good # -1: max size: 4 Kb <-- good # Positive numbers mean store up to _exactly_ that number of elements # per list node. # The highest performing option is usually -2 (8 Kb size) or -1 (4 Kb size), # but if your use case is unique, adjust the settings as necessary. list-max-ziplist-size -2 # Lists may also be compressed. # Compress depth is the number of quicklist ziplist nodes from *each* side of # the list to *exclude* from compression. The head and tail of the list # are always uncompressed for fast push/pop operations. Settings are: # 0: disable all list compression # 1: depth 1 means "don''t start compressing until after 1 node into the list, # going from either the head or tail" # So: [head]->node->node->...->node->[tail] # [head], [tail] will always be uncompressed; inner nodes will compress. # 2: [head]->[next]->node->node->...->node->[prev]->[tail] # 2 here means: don''t compress head or head->next or tail->prev or tail, # but compress all nodes between them. # 3: [head]->[next]->[next]->node->node->...->node->[prev]->[prev]->[tail] # etc. list-compress-depth 0 # Sets have a special encoding in just one case: when a set is composed # of just strings that happen to be integers in radix 10 in the range # of 64 bit signed integers. # The following configuration setting sets the limit in the size of the # set in order to use this special memory saving encoding. set-max-intset-entries 512 # Similarly to hashes and lists, sorted sets are also specially encoded in # order to save a lot of space. This encoding is only used when the length and # elements of a sorted set are below the following limits: zset-max-ziplist-entries 128 zset-max-ziplist-value 64 # HyperLogLog sparse representation bytes limit. The limit includes the # 16 bytes header. When an HyperLogLog using the sparse representation crosses # this limit, it is converted into the dense representation. # # A value greater than 16000 is totally useless, since at that point the # dense representation is more memory efficient. # # The suggested value is ~ 3000 in order to have the benefits of # the space efficient encoding without slowing down too much PFADD, # which is O(N) with the sparse encoding. The value can be raised to # ~ 10000 when CPU is not a concern, but space is, and the data set is # composed of many HyperLogLogs with cardinality in the 0 - 15000 range. hll-sparse-max-bytes 3000 # Active rehashing uses 1 millisecond every 100 milliseconds of CPU time in # order to help rehashing the main Redis hash table (the one mapping top-level # keys to values). The hash table implementation Redis uses (see dict.c) # performs a lazy rehashing: the more operation you run into a hash table # that is rehashing, the more rehashing "steps" are performed, so if the # server is idle the rehashing is never complete and some more memory is used # by the hash table. # # The default is to use this millisecond 10 times every second in order to # actively rehash the main dictionaries, freeing memory when possible. # # If unsure: # use "activerehashing no" if you have hard latency requirements and it is # not a good thing in your environment that Redis can reply from time to time # to queries with 2 milliseconds delay. # # use "activerehashing yes" if you don''t have such hard requirements but # want to free memory asap when possible. activerehashing yes # The client output buffer limits can be used to force disconnection of clients # that are not reading data from the server fast enough for some reason (a # common reason is that a Pub/Sub client can''t consume messages as fast as the # publisher can produce them). # # The limit can be set differently for the three different classes of clients: # # normal -> normal clients including MONITOR clients # slave -> slave clients # pubsub -> clients subscribed to at least one pubsub channel or pattern # # The syntax of every client-output-buffer-limit directive is the following: # # client-output-buffer-limit <class> <hard limit> <soft limit> <soft seconds> # # A client is immediately disconnected once the hard limit is reached, or if # the soft limit is reached and remains reached for the specified number of # seconds (continuously). # So for instance if the hard limit is 32 megabytes and the soft limit is # 16 megabytes / 10 seconds, the client will get disconnected immediately # if the size of the output buffers reach 32 megabytes, but will also get # disconnected if the client reaches 16 megabytes and continuously overcomes # the limit for 10 seconds. # # By default normal clients are not limited because they don''t receive data # without asking (in a push way), but just after a request, so only # asynchronous clients may create a scenario where data is requested faster # than it can read. # # Instead there is a default limit for pubsub and slave clients, since # subscribers and slaves receive data in a push fashion. # # Both the hard or the soft limit can be disabled by setting them to zero. client-output-buffer-limit normal 0 0 0 client-output-buffer-limit slave 256mb 64mb 60 client-output-buffer-limit pubsub 32mb 8mb 60 # Redis calls an internal function to perform many background tasks, like # closing connections of clients in timeout, purging expired keys that are # never requested, and so forth. # # Not all tasks are performed with the same frequency, but Redis checks for # tasks to perform according to the specified "hz" value. # # By default "hz" is set to 10. Raising the value will use more CPU when # Redis is idle, but at the same time will make Redis more responsive when # there are many keys expiring at the same time, and timeouts may be # handled with more precision. # # The range is between 1 and 500, however a value over 100 is usually not # a good idea. Most users should use the default of 10 and raise this up to # 100 only in environments where very low latency is required. hz 10 # When a child rewrites the AOF file, if the following option is enabled # the file will be fsync-ed every 32 MB of data generated. This is useful # in order to commit the file to the disk more incrementally and avoid # big latency spikes. aof-rewrite-incremental-fsync yes # Generated by CONFIG REWRITE
注意：
dir "/usr/src/redis/data" #指定工作目录
logfile "/usr/src/redis/log/redis.log" #指定日志文件
daemonize no #不要以守护进程的形式运行 不然不能挂起
requirepass 123456 #设置密码
cluster-enabled no #设置非集群
protected-mode no #关闭保护模式，可以外网访问
准备从节点配置
# slaveof <masterip> <masterport> #配置主节点ip和端口，不推荐直接配置文件配置 masterauth 123456 #主节点密码
配置完后准备生成容器
docker run -itd -v /usr/docker/redis/master:/usr/src/redis/ -p 6380:6379 --name redis-master --network=redis-network --ip=192.168.1.2 redis
docker run -itd -v /usr/docker/redis/slave:/usr/src/redis/ -p 6381:6379 --name redis-slave --network=redis-network --ip=192.168.1.3 redis
进入从节点的 redis-cli
SLAVEOF 192.168.1.2 6379 #设置主节点
info replication #查看信息
# Replication
role:slave
master_host:192.168.1.2
master_port:6379
master_link_status:up #说明成功
master_last_io_seconds_ago:6
master_sync_in_progress:0
slave_repl_offset:23101
slave_priority:100
slave_read_only:1
connected_slaves:0
master_replid:1b4d67317edf085b684a7a49b59d85a68a76e169
master_replid2:0000000000000000000000000000000000000000
master_repl_offset:23101
second_repl_offset:-1
repl_backlog_active:1
repl_backlog_size:1048576
repl_backlog_first_byte_offset:1
repl_backlog_histlen:23101
cat /usr/src/redis/log/redis.log #查看日志可以看出是否成功，或者失败原因
注意：主从配置后会删除从节点的数据，第一次同步为全量同步
主从复制原理
主从复制的原理以及过程必须要掌握，这样我们才知道为什么会出现这些问题
主从复制过程大体可以分为 3 个阶段：连接建立阶段（即准备阶段）、数据同步阶段、命令传播阶段。
在从节点执行 slaveof 命令后，复制过程便开始运作，下面图示大概可以看到， 从图中可以看出复制过程大致分为 6 个过程
主从配置之后的日志记录也可以看出这个流程
1）保存主节点（master）信息。 执行 slaveof 后 Redis 会打印如下日志：
2）从节点（slave）内部通过每秒运行的定时任务维护复制相关逻辑，当定时任务发现存在新的主节点后，会尝试与该节点建立网络连接
从节点与主节点建立网络连接
从节点会建立一个 socket 套接字，从节点建立了一个端口为 51234 的套接字，专门用于接受主节点发送的复制命令。从节点连接成功后打印如下日志：
如果从节点无法建立连接，定时任务会无限重试直到连接成功或者执行 slaveof no one 取消复制
关于连接失败，可以在从节点执行 info replication 查看 master_link_down_since_seconds 指标，它会记录与主节点连接失败的系统时间。从节点连接主节点失败时也会每秒打印如下日志，方便发现问题：如 Error condition on socket for SYNC: {socket_error_reason}
3）发送 ping 命令。
连接建立成功后从节点发送 ping 请求进行首次通信， ping 请求主要目的如下：
检测主从之间网络套接字是否可用。
检测主节点当前是否可接受处理命令
如果发送 ping 命令后，从节点没有收到主节点的 pong 回复或者超时，比如网络超时或者主节点正在阻塞无法响应命令，从节点会断开复制连接，下次定时任务会发起重连。
从节点发送的 ping 命令成功返回，Redis 打印如下日志，并继续后续复制流程：
4）权限验证。
如果主节点设置了 requirepass 参数，则需要密码验证，从节点必须配置 masterauth 参数保证与主节点相同的密码才能通过验证；如果验证失败复制将终止，从节点重新发起复制流程。
5）同步数据集。
主从复制连接正常通信后，对于首次建立复制的场景，主节点会把持有的数据全部发送给从节点，这部分操作是耗时最长的步骤。
6）命令持续复制。
当主节点把当前的数据同步给从节点后，便完成了复制的建立流程。接下来主节点会持续地把写命令发送给从节点，保证主从数据一致性。
3.docker学习笔记之入门，redis主从配置2 理论
全量复制
用于初次复制或其它无法进行部分复制的情况，将主节点中的所有数据都发送给从节点，是一个非常重型的操作，当数据量较大时，会对主从节点和网络造成很大的开销
部分复制
用于处理在主从复制中因网络闪断等原因造成的数据丢失场景，当从节点再次连上主节点后，如果（条件允许)，主节点会补发丢失数据给从节点。因为补发的数据远远小于全量数据，可以有效避免全量复制的过高开销，需要注意的是，如果网络中断时间过长，造成主节点没有能够完整地保存中断期间执行的写命令，则无法进行部分复制，仍使用全量复制
复制偏移量
参与复制的主从节点都会维护自身复制偏移量。主节点（master）在处理完写入命令后，会把命令的字节长度做累加记录，统计信息在 info relication 中的master_repl_offset 指标中：
127.0.0.1:6379> info replication
从节点（slave）每秒钟上报自身的复制偏移量给主节点，因此主节点也会保存从节点的复制偏移量，统计指标如下：
从节点在接收到主节点发送的命令后，也会累加记录自身的偏移量。统计信息在 info relication 中的 slave_repl_offset 中
复制积压缓冲区
复制积压缓冲区是保存在主节点上的一个固定长度的队列，默认大小为1MB，当主节点有连接的从节点（slave）时被创建，这时主节点（master）响应写命令时，不但会把命令发送给从节点，还会写入复制积压缓冲区。
在命令传播阶段，主节点除了将写命令发送给从节点，还会发送一份给复制积压缓冲区，作为写命令的备份；除了存储写命令，复制积压缓冲区中还存储了其中的每个字节对应的复制偏移量(offset) 。由于复制积压缓冲区定长且先进先出，所以它保存的是主节点最近执行的写命令；时间较早的写命令会被挤出缓冲区。
如图所示:
1、Redis 内部会发出一个同步命令，刚开始是 Psync 命令，Psync ? -1表示要求 master 主机同步数据
2、主机会向从机发送 runid 和 offset，因为 slave 并没有对应的 offset，所以是全量复制
3、从机 slave 会保存 主机master 的基本信息 save masterInfo
4、主节点收到全量复制的命令后，执行bgsave（异步执行），在后台生成RDB文件（快照）（在较新的版本里可以不生成快照无磁盘化传输），并使用一个缓冲区（称为复制缓冲区）记录从现在开始执行的所有写命令
5、主机send RDB 发送 RDB 文件给从机
6、发送缓冲区数据
7、刷新旧的数据，从节点在载入主节点的数据之前要先将老数据清除
8、加载 RDB 文件将数据库状态更新至主节点执行bgsave时的数据库状态然后再缓冲区数据的加载。
全量复制开销，主要有以下几项。
bgsave 时间
RDB 文件网络传输时间
从节点清空数据的时间
从节点加载 RDB 的时间
部分复制
部分复制是 Redis 2.8 以后出现的，之所以要加入部分复制，是因为全量复制会产生很多问题，比如像上面的时间开销大、无法隔离等问题， Redis 希望能够在master 出现抖动（相当于断开连接）的时候，可以有一些机制将复制的损失降低到最低
1、如果网络抖动（连接断开 connection lost）
2、主机master 还是会写 replbackbuffer（复制缓冲区）
3、从机slave 会继续尝试连接主机
4、从机slave 会把自己当前 runid 和偏移量传输给主机 master，并且执行 pysnc 命令同步
5、如果 master 发现你的偏移量是在缓冲区的范围内，就会返回 continue 命令
6、同步了 offset 的部分数据，所以部分复制的基础就是偏移量 offset。
正常情况下redis是如何决定是全量复制还是部分复制
从节点将offset发送给主节点后，主节点根据offset和缓冲区大小决定能否执行部分复制:
如果offset偏移量之后的数据，仍然都在复制积压缓冲区里，则执行部分复制；
如果offset偏移量之后的数据已不在复制积压缓冲区中（数据已被挤出），则执行全量复制。
缓冲区大小调节：
由于缓冲区长度固定且有限，因此可以备份的写命令也有限，当主从节点offset的差距过大超过缓冲区长度时，将无法执行部分复制，只能执行全量复制。反过来说，为了提高网络中断时部分复制执行的概率，可以根据需要增大复制积压缓冲区的大小(通过配置repl-backlog-size)来设置；
例如 如果网络中断的平均时间是60s，而主节点平均每秒产生的写命令(特定协议格式)所占的字节数为100KB，则复制积压缓冲区的平均需求为6MB，保险见，可以设置为12MB，来保证绝大多数断线情况都可以使用部分复制。
服务器运行ID(runid)
每个Redis节点(无论主从)，在启动时都会自动生成一个随机ID(每次启动都不一样)，由40个随机的十六进制字符组成；runid用来唯一识别一个Redis节点。 通过info server命令，可以查看节点的runid：
主从节点初次复制时，主节点将自己的runid发送给从节点，从节点将这个runid保存起来；当断线重连时，从节点会将这个runid发送给主节点；主节点根据runid判断能否进行部分复制：
如果从节点保存的runid与主节点现在的runid相同，说明主从节点之前同步过，主节点会继续尝试使用部分复制(到底能不能部分复制还要看offset和复制积压缓冲区的情况)
如果从节点保存的runid与主节点现在的runid不同，说明从节点在断线前同步的Redis节点并不是当前的主节点，只能进行全量复制。
主从复制的常用相关配置
从数据库配置
1) slaveof <masterip> <masterport> #slave实例需要配置该项，指向master的（ip, port）。 启动后自动设置主从
2) masterauth <master-password> #主节点密码 如果master实例启用了密码保护，则该配置项需填master的启动密码；若master未启用密码，该配置项需要注释掉
3) slave-serve-stale-data #指定 slave 与 master 连接中断时的动作。默认为yes，表明slave会继续应答来自client的请求，但这些数据可能已经过期（因为连接中断导致无法从 master同步）。若配置为no，则slave除正常应答"INFO"和"SLAVEOF"命令外，其余来自客户端的请求命令均会得到" SYNC with master in progress "的应答，直到该 slave 与master 的连接重建成功或该 slave 被提升为 master 。
4) slave-read-only #指定slave是否只读，默认为yes。若配置为no，这表示slave是可写的，但写的内容在主从同步完成后会被删掉。
5) repl-disable-tcp-nodelay #指定向slave同步数据时，是否禁用 socket 的 NO_DELAY 选项。若配置为yes，则禁用 NO_DELAY ，则TCP协议栈会合并小包统一发送，这样可以减少主从节点间的包数量并节省带宽，但会增加数据同步到slave的时间。若配置为no，表明启用 NO_DELAY ，则TCP协议栈不会延迟小包的发送时机，这样数据同步的延时会减少，但需要更大的带宽。通常情况下，应该配置为no以降低同步延时，但在主从节点间网络负载已经很高的情况下，可以配置为yes。
6) slave-priorit #指定 slave 的优先级。在不只1个 slave 存在的部署环境下，当 master 宕机时， Redis Sentinel 会将priority值最小的slave提升为master。需要注意的是，若该配置项为0，则对应的slave永远不会被 Redis Sentinel 自动提升为 master 。
主从配置参数参考
###########从库##############
#设置该数据库为其他数据库的从数据库（如果用到哨兵就不建议使用这种）
slaveof <masterip> <masterport>
#主从复制中，设置连接master服务器的密码（前提master启用了认证）
masterauth <master-password>
slave-serve-stale-data yes
# 当从库同主库失去连接或者复制正在进行，从库有两种运行方式：
# 1) 如果slave-serve-stale-data设置为yes(默认设置)，从库会继续相应客户端的请求
# 2) 如果slave-serve-stale-data设置为no，除了INFO和SLAVOF命令之外的任何请求都会返回一个错误"SYNC with master in progress"
#当主库发生宕机时候，哨兵会选择优先级最高的一个称为主库，从库优先级配置默认100，数值越小优先级越高
slave-priority 100
#从节点是否只读；默认yes只读，为了保持数据一致性，应保持默认
slave-read-only yes
########主库配置##############
#在slave和master同步后（发送psync/sync），后续的同步是否设置成TCP_NODELAY假如设置成yes，则redis会合并小的TCP包从而节省带宽，但会增加同步延迟（40ms），造成master与slave数据不一致假如设置成no，则redis master会立即发送同步数据，没有延迟
#前者关注性能，后者关注一致性
repl-disable-tcp-nodelay no
#从库会按照一个时间间隔向主库发送PING命令来判断主服务器是否在线，默认是10秒
repl-ping-slave-period 10
#复制积压缓冲区大小设置
repl-backlog-size 1mb
#master没有slave一段时间会释放复制缓冲区的内存，repl-backlog-ttl用来设置该时间长度。单位为秒。
repl-backlog-ttl 3600
#redis提供了可以让master停止写入的方式，如果配置了min-slaves-to-write，健康的slave的个数小于N，mater就禁止写入。master最少得有多少个
健康的slave存活才能执行写命令。这个配置虽然不能保证N个slave都一定能接收到master的写操作，但是能避免没有足够健康的slave的时候，master不
能写入来避免数据丢失。设置为0是关闭该功能。
min-slaves-to-write 3
min-slaves-max-lag 10
#从服务器的数量少于3个，或者三个从服务器的延迟（lag）值都大于或等于10秒时，主服务器将拒绝执行写命令，这里的延迟值就是info replication命令的lag 值docker run --privileged -itd -v /usr/docker/redis/slave2:/usr/src/redis -p 6382:6379 --name redis-slave2 --network=redis-network --ip=192.168.1.4 redis
#--privileged 给容器网络操作的权限
主从复制进阶常见问题解决
1、读写分离
2、数据延迟
3、主从配置不一致
4、规避全量复制
5、规避复制风暴
读写分离
读流量分摊到从节点。这是个非常好的特性，如果一个业务只需要读数据，那么我们只需要连一台 slave 从机读数据。
虽然读写有优势，能够让读这部分分配给各个 slave 从机，如果不够，直接加 slave 机器就好了。但是也会出现以下问题。
复制数据延迟
可能会出现 slave 延迟导致读写不一致等问题，当然你也可以使用监控偏移量 offset ，如果 offset 超出范围就切换到 master 上,逻辑切换，而具体延迟多少，可以通过 info replication 的 offset 指标进行排查。
对于无法容忍大量延迟场景，可以编写外部监控程序监听主从节点的复制偏移量，当延迟较大时触发报警或者通知客户端避免读取延迟过高的从节点同时从节点的 slave-serve-stale-data 参数也与此有关，它控制这种情况下从节点的表现 当从库同主机失去连接或者复制正在进行，从机库有两种运行方式：
1) 如果slave-serve-stale-data设置为yes(默认设置)，从库会继续响应客户端的请求。
2) 如果slave-serve-stale-data设置为no，除去INFO和SLAVOF命令之外的任何请求都会返回一个错误”SYNC with master in progress”。
例子：模拟网络延迟
docker run --privileged -itd -v /usr/docker/redis/slave2:/usr/src/redis -p 6382:6379 --name redis-slave2 --network=redis-network --ip=192.168.1.4 redis
--privileged Docker 容器将拥有访问主机所有设备的权限
通过linux下的控流工具，模拟网络延迟，用代码模拟下，因为对于网络的操作属于特殊权限所以需要添加 --privileged 参数
centos:
yum install iproute
alpine:
apk add install iproute2
进入到容器之后配置延迟5s
tc qdisc add dev eth0 root netem delay 5000ms
tc qdisc del dev eth0 root netem delay 5000ms
异步复制导致数据丢失
因为master->slave的复制是异步，所以可能有部分还没来得及复制到slave就宕机了，此时这些部分数据就丢失了。
怎么解决?(请记住只能降低到可控范围,没办法做到100%不丢失)
#最少有多少台从机器才能写入
min-slaves-to-write 1
#从节点最大延迟时间,延迟小于min-slaves-max-lag秒的slave才认为是健康的slave
min-slaves-max-lag 10
要求至少有1个slave，数据复制和同步的延迟不能超过10秒，如果说一旦所有的slave，数据复制和同步的延迟都超过了10秒钟，那么这个时候，master就不会再接收任何请求了
有了min-slaves-max-lag这个配置，就可以确保说，一旦slave复制数据和ack延时太长，就认为可能master宕机后损失的数据太多了，那么就拒绝写请求，这样可以把master宕机时由于部分数据未同步到slave导致的数据丢失降低到可控范围内
如何选择，要不要读写分离？
没有最合适的方案，只有最合适的场景，读写分离需要业务可以容忍一定程度的数据不一致，适合读多写少的业务场景，读写分离，是为了什么，主要是因为要建立一主多从的架构，才能横向任意扩展 slave node 去支撑更大的读吞吐量。
从节点故障问题
对于从节点的故障问题，需要在客户端维护一个可用从节点可用列表，当从节 点故障时，立刻切换到其他从节点或主节点，之后讲解redis Cluster 时候可以解决这个问题
配置不一致
主机和从机不同，经常导致主机和从机的配置不同，并带来问题。
数据丢失： 主机和从机有时候会发生配置不一致的情况，例如 maxmemory 不一致，如果主机配置 maxmemory 为8G，从机 slave 设置为4G，这个时候是可以用的，而且还不会报错。但是如果要做高可用，让从节点变成主节点的时候，就会发现数据已经丢失了，而且无法挽回。
规避全量复制
全量复制指的是当 slave 从机断掉并重启后，runid 产生变化而导致需要在 master 主机里拷贝全部数据。这种拷贝全部数据的过程非常耗资源。全量复制是不可避免的，例如第一次的全量复制是不可避免的，这时我们需要选择小主节点，且 maxmemory 值不要过大，这样就会比较快。同时选择在低峰值的时候做全量复制。
造成全量复制的原因
1. 是主从机的运行 runid 不匹配。解释一下，主节点如果重启， runid 将会发生变化。如果从节点监控到 runid 不是同一个，它就会认为你的节点不安全。当发生故障转移的时候，如果主节点发生故障，那么从机就会变成主节点。
2. 复制缓冲区空间不足，比如默认值1M，可以部分复制。但如果缓存区不够大的话，首先需要网络中断，部分复制就无法满足。其次需要增大复制缓冲区配置（relbacklogsize），对网络的缓冲增强。
怎么解决？
在一些场景下，可能希望对主节点进行重启，例如主节点内存碎片率过高，或者希望调整一些只能在启动时调整的参数。如果使用普通的手段重启主节点，会使得runid发生变化，可能导致不必要的全量复制。为了解决这个问题，Redis提供了debug reload的重启方式：重启后，主节点的runid和offset都不受影响，避免了全量复制。
单机器的复制风暴
1、当一个主机下面挂了很多个 slave 从机的时候，主机 master 挂了，这时 master 主机重启后，因为 runid 发生了变化，所有的 slave 从机都要做一次全量复制。这将引起单节点和单机器的复制风暴，开销会非常大。
解决：
可以采用树状结构降低多个从节点对主节点的消耗
从节点采用树状树非常有用，网络开销交给位于中间层的从节点，而不必消耗顶层的主节点。但是这种树状结构也带来了运维的复杂性，增加了手动和自动处理故障转移的难度
2、由于 Redis 的单线程架构，通常单台机器会部署多个 Redis 实例。当一台机器（machine）上同时部署多个主节点 （master） 时，如果每个 master 主机只有一台 slave 从机，那么当机器宕机以后，会产生大量全量复制。这种情况是非常危险的情况，带宽马上会被占用，会导致不可用。
解决：
1、应该把主节点尽量分散在多台机器上，避免在单台机器上部署过多的主节点。
2、当主节点所在机器故障后提供故障转移机制，避免机器恢复后进行密集的全量复制
docker mysql 主从配置
1、首先创建两个文件my-m.cnf（主库配置） 、my-s.cnf（从库配置）
my-m.cnf 内容如下
# Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; version 2 of the License.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
#
# The MySQL Community Server configuration file.
#
# For explanations see
# http://dev.mysql.com/doc/mysql/en/server-system-variables.html
[client]
port = 3306
socket = /var/run/mysqld/mysqld.sock
[mysqld_safe]
pid-file = /var/run/mysqld/mysqld.pid
socket = /var/run/mysqld/mysqld.sock
nice = 0
[mysqld]
user = mysql
pid-file = /var/run/mysqld/mysqld.pid
socket = /var/run/mysqld/mysqld.sock
port = 3306
basedir = /usr
datadir = /var/lib/mysql
tmpdir = /tmp
lc-messages-dir = /usr/share/mysql
explicit_defaults_for_timestamp
log-bin = mysql-bin
server-id = 1
# Instead of skip-networking the default is now to listen only on
# localhost which is more compatible and is not less secure.
#bind-address = 127.0.0.1
#log-error = /var/log/mysql/error.log
# Recommended in standard MySQL setup
sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
# * IMPORTANT: Additional settings that can override those from this file!
# The files must end with ''.cnf'', otherwise they''ll be ignored.
#
!includedir /etc/mysql/conf.d/
主要是这两行，只需要在原来的配置里面加上就行
log-bin = mysql-bin
server-id = 1 my-s.cnf 内容如下
# Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; version 2 of the License.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
#
# The MySQL Community Server configuration file.
#
# For explanations see
# http://dev.mysql.com/doc/mysql/en/server-system-variables.html
[client]
port = 3306
socket = /var/run/mysqld/mysqld.sock
[mysqld_safe]
pid-file = /var/run/mysqld/mysqld.pid
socket = /var/run/mysqld/mysqld.sock
nice = 0
[mysqld]
user = mysql
pid-file = /var/run/mysqld/mysqld.pid
socket = /var/run/mysqld/mysqld.sock
port = 3306
basedir = /usr
datadir = /var/lib/mysql
tmpdir = /tmp
lc-messages-dir = /usr/share/mysql
explicit_defaults_for_timestamp
log-bin = mysql-bin
server-id = 2
# Instead of skip-networking the default is now to listen only on
# localhost which is more compatible and is not less secure.
#bind-address = 127.0.0.1
#log-error = /var/log/mysql/error.log
# Recommended in standard MySQL setup
sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
# * IMPORTANT: Additional settings that can override those from this file!
# The files must end with ''.cnf'', otherwise they''ll be ignored.
#
!includedir /etc/mysql/conf.d/
同样，主要的是这两行
log-bin = mysql-bin
server-id = 22、OK，有了配置文件，就可以启动mysql了，先启动主库
$ docker run -d -e MYSQL_ROOT_PASSWORD=admin --name mysql-master -v /soft/my-m.cnf:/etc/mysql/my.cnf -p 3307:3306 mysql3、启动从库
$ docker run -d -e MYSQL_ROOT_PASSWORD=admin --name mysql-slave -v /soft/my-s.cnf:/etc/mysql/my.cnf -p 3308:3306 mysql4、连接主库，并运行以下命令，创建一个用户用来同步数据
$ GRANT REPLICATION SLAVE ON *.* to ''backup''@''%'' identified by ''123456'';5、查看主库状态
$ show master status;记住File、Position的值，如果没查到数据，请检查第一、第二步，配置问题。
我查出来的是mysql-bin.000004、312
6、连接到从库，运行以下命令，设置主库链接
$ change master to master_host=''121.32.32.54'',master_user=''backup'',master_password=''123456'',
master_log_file=''mysql-bin.000004'',master_log_pos=312,master_port=3307;7、启动同步
$ start slave;8、查看同步状态
$ show slave status如果看到Waiting for master send event.. 什么的就成功了，你现在在主库上的修改，都会同步到从库上
Docker mysql主从配置
一：MysqL基于Docker的主从复制搭建
1：安装docker，安装步骤可见我之前的文章：
docker ps 命令查询当前的容器状态，这就是我们最后要达到的效果。
2：首先拉取MysqL官方镜像
bash> docker pull MysqL:5.7
演示环境是在同一台服务器上部署。因为docker创建容器时默认采用bridge网络，会自行分配ip，不允许指定，重启容器会导致ip变更。
所以我们需要创建自定义的bridge网络，这样创建容器的时候才能指定ip。
bash> docker network create --subnet=172.18.0.0/16 mynetwork
3：创建三个MysqL（一主两从）容器：
docker run -p 3306:3306 --name MysqL_master --net mynetwork --ip 172.18.0.36 -e TZ=Asia/Shanghai -v /home/data/docker/MysqL/MysqL1/logs:/logs -v /home/data/docker/MysqL/MysqL1/data:/var/lib/MysqL -v /home/data/docker/MysqL/MysqL1/conf:/etc/MysqL -e MysqL_ROOT_PASSWORD=Abcd12345 -d --restart=always MysqL:5.7 docker run -p 3307:3306 --name MysqL_slave1 --net mynetwork --ip 172.18.0.37 -e TZ=Asia/Shanghai -v /home/data/docker/MysqL/MysqL2/logs:/logs -v /home/data/docker/MysqL/MysqL2/data:/var/lib/MysqL -v /home/data/docker/MysqL/MysqL2/conf:/etc/MysqL -e MysqL_ROOT_PASSWORD=Abcd12345 -d --restart=always MysqL:5.7 docker run -p 3308:3306 --name MysqL_slave2 --net mynetwork --ip 172.18.0.38 -e TZ=Asia/Shanghai -v /home/data/docker/MysqL/MysqL3/logs:/logs -v /home/data/docker/MysqL/MysqL3/data:/var/lib/MysqL -v /home/data/docker/MysqL/MysqL3/conf:/etc/MysqL -e MysqL_ROOT_PASSWORD=Abcd12345 -d --restart=always MysqL:5.7
上面的docker run命令中的参数都有其独特的含义，比如 -p 3307:3306 表示当前环境主键的端口(3307)：docker容器内的端口(3306)
-v /home/data/docker/MysqL/MysqL1/conf:/etc/MysqL 这个配置的是MysqL的配置文件路径，
对于MysqL_master 需要在当前系统/home/data/docker/MysqL/MysqL1/conf目录下创建 my.cnf文件，内容如下：
[MysqLd] pid-file = /var/run/MysqLd/MysqLd.pid socket = /var/run/MysqLd/MysqLd.sock datadir = /var/lib/MysqL #log-error = /var/log/MysqL/error.log # By default we only accept connections from localhost #bind-address = 127.0.0.1 # disabling symbolic-links is recommended to prevent assorted security risks symbolic-links=0 log-bin=/var/lib/MysqL/MysqL-bin server-id=36 ## 主从复制的格式（mixed,statement,row，默认格式是statement） binlog_format=mixed ## 二进制日志自动删除/过期的天数。默认值为0，表示不自动删除。 expire_logs_days=7 max_allowed_packet=20M
剩余的两个从库配置，/home/data/docker/MysqL/MysqL2/conf目录下创建 my.cnf文件
[MysqLd] server-id=37 log-bin=/var/lib/MysqL/MysqL-slave1-bin
/home/data/docker/MysqL/MysqL3/conf目录下创建 my.cnf文件
[MysqLd] server-id=38 log-bin=/var/lib/MysqL/MysqL-slave2-bin
配置修改完成后，重启容器：
docker restart MysqL_master
docker restart MysqL_slave1
docker restart MysqL_slave2
二：主从配置
1：进入主库：docker exec -it MysqL_master /bin/bash
bash> MysqL -uroot -p MysqL> SHOW MASTER STATUS; File | Position | binlog_Do_DB | binlog_Ignore_DB | Executed_Gtid_Set | +------------------+----------+--------------+------------------+-------------------+ | MysqL-bin.000001 | 154|
2：同步MysqL_slave1 和 MysqL_slave2
# 进入MysqL_salve1
bash> docker exec -it MysqL_slave1 /bin/bash
# 执行同步 MysqL> change master to master_host='172.18.0.36', master_user='root',master_password='Abcd12345',master_port=3306,master_log_file='MysqL-bin.000001',master_log_pos=154,master_connect_retry=30; MysqL> start slave;
# 进入MysqL_salve2master_port：Master的端口号，指的是容器的端口号 master_user：用于数据同步的用户 master_password：用于同步的用户的密码 master_log_file：指定 Slave 从哪个日志文件开始复制数据，即主库中提到的 File 字段的值 master_log_pos：从哪个 Position 开始读，即主库中提到的 Position 字段的值 master_connect_retry：如果连接失败，重试的时间间隔，单位是秒，默认是60秒
bash> docker exec -it MysqL_slave2 /bin/bash
# 执行同步 MysqL> change master to master_host='172.18.0.36', master_user='root',master_password='Abcd12345',master_port=3306,master_log_file='MysqL-bin.000001',master_log_pos=154,master_connect_retry=30; MysqL> start slave;
最后，可以自己验证下同步的效果了。
今天的关于在 Docker 中进行 Redis 主从配置和docker搭建redis主从的分享已经结束，谢谢您的关注，如果想了解更多关于2.docker 学习笔记之入门，redis 主从配置 1、3.docker学习笔记之入门，redis主从配置2 理论、docker mysql 主从配置、Docker mysql主从配置的相关知识，请在本站进行查询。
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