docker介绍
docker
为什么会有docker出现?
一款产品从开发到上线,从操作系统到运行环境,再到应用配置,作为开发+运维直接的协作我们需要关心很多东西,这也是互联网公司不得 不面对问题,特别是各种版本迭代之后,不同版本的兼容,都是对运维人员考验
软件可以带环境安装,也就是说安装的时候把原始环境一模一样的复制过来,开发人员利用Docker可以消除协作编码时的’不能跑通’的问题.
Docker 理念
一处构建,处处都能够运行
docker能干什么?
让开发者不必安装和配置复杂的数据库,也无需在不兼容语言工具链版本之间切换时担心。应用容器化之后,其复杂性就被转移到能够轻松构建、共享和运行的容器中。当有新同事安排到新的代码库时,无需再费时费力地安装软件和解释设置过程。以 Dockerfile 文件形式发布的代码使用起来非常简单:首先安装 Docker 和编辑器,然后拉取作为 Docker 镜像打包在一起的依赖资源,短短数分钟,就能够构建和调试应用了。
官网:
中文官网:http://www.docker-cn.com/
docker-hub官网:http://hub.docker.com
docker命令
docker version #查看docker版本 docker info #查看docker信息 docker --help #查看docker指令的使用方法
镜像
镜像概念
- 是一种轻量级,可执行的独立软件包,用于打包软件运行环境和基于运行环境开发的软件,简单理解为类
- union文件系统是一种分层,轻量级并且高性能的文件系统,它支持对文件系统的修改作为一次提交来一层层的叠加,同时可以将不同目录挂在到同一个虚拟系统下.Union文件系统是docker镜像的基础.镜像可以通过分层来进行集成,基于基础镜像,可以制作各种具体的应用镜像
- 一次同时加载多个文件系统,在外面看起来,只能看到一个文件系统,联合加载会把各层系统叠加起来,这样最总文件系统会包含所有底层的文件和目录
最大的好处就是共享资源:
比如:有多个镜像都从相同的base镜像构建而来,那么宿主机只需要在磁盘上保存一份base镜像,同时内存中也只需要加载一份base镜像,就可以为所有容器服务了.而且镜像的每一层都是可以被共享的
镜像命令
查看镜像
docker images #查看本机上的镜像 -a #列出本机所有的镜像(包含映象层) -q #显示镜像ID --digests #显示镜像摘要 --no-trunc #显示完整镜像信息
查找镜像
docker search 镜像名 #docker search -s 30 mysql #查找超过30个收藏的mysql镜像
拉镜像到本地
docker pull 镜像 #docker pull mysql
删除镜像
#删除单个镜像 docker rmi -f 镜像名/镜像id #删除多个 docker -rmi -f 镜像1 镜像2 #全部删除 docker -rmi -f $(docker imags -qa
容器
容器是用镜像创建的运行实例 它可以被启动,停止,删除,每个容器都是可以相互隔离保证安全的平台,可以把容器看做一个简易版的linux坏境
容器镜像是轻量的、可执行的独立软件包,包含软件运行所需的所有内容:代码、运行时环境、系统工具、系统库和设置。容器化软件适用于基于 Linux 和 Windows 的应用,在任何环境中都能够始终如一地运行。容器赋予了软件独立性,使其免受外在环境差异(例如,开发和预演环境的差异)的影响,从而有助于减少团队间在相同基础设施上运行不同软件时的冲突。
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轻量
- 在一台机器上运行的多个 Docker 容器可以共享这台机器的操作系统内核;它们能够迅速启动,只需占用很少的计算和内存资源。镜像是通过文件系统层进行构造的,并共享一些公共文件。这样就能尽量降低磁盘用量,并能更快地下载镜像。
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标准
- Docker 容器基于开放式标准,能够在所有主流 Linux 版本、Microsoft Windows 以及包括 VM、裸机服务器和云在内的任何基础设施上运行。
- 安全
- Docker 赋予应用的隔离性不仅限于彼此隔离,还独立于底层的基础设施。Docker 默认提供最强的隔离,因此应用出现问题,也只是单个容器的问题,而不会波及到整台机器。
容器对于虚拟机有什么优点?
- docker有着比虚拟机更少的抽象层.由于docker不需要Hypevisor实现硬件资源虚拟化,在运行docker容器上的程序直接使用都是实际物理机的硬件资源,因此在cpu和内存的利用率上docker将会在效率上有明显优势
- docker利用的是宿主机内核,不需要guest os.因此当新建一个容器时,docker不需要和虚拟机一样重新加载一个操作系统内核.避免加载操作系统内核比较浪费时间的过程.所以docker开启时秒级的,而虚拟机时分钟级别的.
容器命令
启动容器
docker run [option] 镜像id --name #为容器定义一个新的名字 -d #后台运行,返回容器id,开启守护容器式 -i #以交互模式运行容器,通常与-t同时使用 -t #为容器分配一个伪终端 -p #指定端口映射 #hostport : containerPort -P #随机分配端口
示例:
docker run -it -p 12345:3306 --name mymysql mysql/镜像id
查看容器
docker ps [option] -a #列出当前所有正在运行的容器+历史上运行过的 -l #显示最新创建的容器 -n #显示最近n个创建的容器 -q #静默模式,只显示容器编号 --no-trunc #不截断输出
启动容器
docker start 镜像名/镜像ID
退出容器
exit #容器停止并且退出 ctrl+p+q #容器不停止退出
停止容器
docker stop 容器id/容器名 #停止容器 docker kill ~ #强制停止容器 docker rm ~ #删除单个容器 删除多个参照镜像
查看容器日志
docker logs -f -t --tail 容器id #-t 加入时间戳 #-f 跟随最新的日志打印 # --tail 显示最后多少条
容器交互
docker exec -it 容器id/镜像名 bashShell 例子: docker exec -it 容器id /bin/bash docker attach 容器id/镜像名 #直接进入容器命令终端,不会启动新的进程 docker exec #是在容器中打开新的终端,并且可以打开新的进程
容器提交
容器卷
docker 理念
将运用与运行的环境打包形成容器运行,运行可以伴随着容器,但是我们队数据的要求是希望持久化的
容器之间希望有可能共享数据
容器卷的设计目的就是数据的持久化,完全独立于容器的生存周期,因此docker不会再容器删除时发删除其挂在的数据卷
特点
- 数据卷可在容器之间共享或重用数据
- 卷中的更改可以直接生效
- 数据卷中的更改不会包含在镜像的更新中
- 数据卷的生命周期一直持续到没有容器使用它位置
命令添加容器卷
docker run -it -v /宿主机绝对路径目录:/容器内目录 镜像名
简单例子:
创建了关联文件夹以后,里面的数据进行共享
无论在目录下哪个文件编写内容都可以进行同步
即使关闭了容器,编写了内容,再开启容器,那么数据也是可以进行同步的
例子2:
容器卷权限
docker run -it -v /宿主机绝对路劲:/容器目录:ro 镜像名 #ro read only
Dockerfile
dockerfile 简单实例
Dockerfile是什么?
Docker images –à DockerFile 是对镜像源码级的描述
例子:
用dockerfile添加数据卷
- 根目录下新建mydocker文件夹并进入
- 可在dockerfile中使用volume指令来给镜像添加一个或者多个容器卷
- file构建
- build后生成镜像 获得一个新的镜像
- run 容器
mkdir mydocker cd mydocker/ vim dockerfile
dockerfile文件:
FROM centos VOLUME [ "/dataVolumeContainer1","/dataVolumeContainer2" ] CMD echo "success" CMD /bin/bash
#根据dockerfile创建一个新的镜像 docker build -f /mydocker/dockerfile -t mycentos #查看新建的镜像 docker images
有了新的镜像之后我们就可以运行容器实例且自带容器卷
我们来看centos的dockerfile
dockerfile的解析过程
- 每条保留字指令都必须为大写字母且后面要跟随至少一个参数
- 指令按照从上到下,顺序执行
- #表示注释
- 每条指令都会创建一个新的镜像层,并对镜像进行提交
总结:
- 从应用角度看,dockerfile,docker镜像和docker容器分别代表软件的三个不同的阶段,
- Dockerfile是软件的原材料
- docker镜像是软件的交付品
- docker容器则可以认为是软件的运行态
dockerfile需要定义一进城需要的一切东西,dockerfile设计的内容包括执行代码或者是文件,环境,变量,依赖包,运行时的环境,动态链接库,操作系统的发行版,服务京城和内核进城
docker镜像,在dockerfile定义一个文件以后,docker build 会产生一个docker镜像,当运行docker镜像时,会真正开始提供服务
dockerfile保留字
FROM #基础镜像,当前新镜像时基于哪个镜像的 MAINTAINER #镜像维护者的姓名和邮箱地址 RUN #容器构建时需要运行的命令 EXPOSE #当前容器对外暴露的端口 ENV # 用来在构建镜像过程中设置环境变量 ADD #将宿主机目录下的文件拷贝进镜像且ADD命令会自动处理url和解压tar压缩包 COPY #将从构建上下文目录中<源目录>的文件/目录复制到一个新的镜像内的<目标路径>位置 #用法 COPY src dest 或者 COPY ["src","dest"] VOLUME #容器数据卷,用于数据的保存和持久化 CMD #dockerfile可以有多个CMD命令,但只有最后一个生效 CMD会被docker run之后的参数替换 ENTRYPOINT #和CMD一样 指定一个容器启动时要运行的命令但是可以追加命令 ONBUILD #当构建一个被继承的dockerfile时运行命令,父镜像在被子镜像继承后父镜像的onbuild被触发
例子1:
构建一个自带vim和net-tool的centos镜像
dockerfile文件内容:
FROM centos MAINTAINER chen<540112587@qq.com> ENV mypth /tmp WORKDIR $mypth RUN yum -y install vim RUN yum -y install net-tools EXPOSE 80 CMD echo $mypth CMD echo "success" CMD /bin/bash
例子2:
CMD和ENTRYPOINT的区别
dockerfile: 返回ip值 FROM centos RUN yum install –y curl CMD [ “curl”,”-s”,”http://ip.cn” ] 根据dockerfile创建镜像 Docker run myip 执行myip镜像 如果执行 docker run myip –i 那么-i会覆盖[]里面的内容 变成 CMD –i那么久会报错
FROM centos RUN yum install –y curl ENTRYPOINT [ “curl”,”-s”,”http://ip.cn” ] 当我们用ENTRYPOINT 的时候是追加的状态 那么运行 docker run myip2 实际上是执行了 curl –s –i http://ip.cn (-i是查看请求头)
例子3
自定制tomcat
安装mysql和redis
例子:4
运行mysql
docker pull mysql:5.6
创建容器且配置数据卷 和mysql密码 docker run -p 12345:3306 --name mysql -v /cxmuse/mysql/conf:/etc/mysql/conf.d
-v /cxmuse/mysql/logs:/logs -v/cxmuse/mysql/data:/var/lib/mysql -e MYSQL_ROOT_PASSWORD=123456 -d mysql:5.6 ############################### 进入mysql docker exec -it 容器id /bin/bash mysql -uroot –p 123456
Win10 连接docker的mysql
ifconfig
用docker做数据库的备份
例子5
用docker 使用redis
docker pull redis:3.2 启动redis容器 docker run -p 6379:6379 -v /cxmuse/myredis/data:/data \
-v /cxmuse/myredis/conf/redis.conf:/usr/local/etc/redis/redis.conf -d redis:3.2 redis-server /usr/local/etc/redis/redis.conf --appendonly yes
配置文件写入redis.conf文件(不是文件夹)
# Redis配置文件样例 # Note on units: when memory size is needed, it is possible to specifiy # 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. # Redis默认不是以守护进程的方式运行,可以通过该配置项修改,使用yes启用守护进程 # 启用守护进程后,Redis会把pid写到一个pidfile中,在/var/run/redis.pid daemonize no # 当Redis以守护进程方式运行时,Redis默认会把pid写入/var/run/redis.pid文件,可以通过pidfile指定 pidfile /var/run/redis.pid # 指定Redis监听端口,默认端口为6379 # 如果指定0端口,表示Redis不监听TCP连接 port 6379 # 绑定的主机地址 # 你可以绑定单一接口,如果没有绑定,所有接口都会监听到来的连接 # bind 127.0.0.1 # 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 755 # 当客户端闲置多长时间后关闭连接,如果指定为0,表示关闭该功能 timeout 0 # 指定日志记录级别,Redis总共支持四个级别:debug、verbose、notice、warning,默认为verbose # debug (很多信息, 对开发/测试比较有用) # 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 verbose # 日志记录方式,默认为标准输出,如果配置为redis为守护进程方式运行,而这里又配置为标准输出,则日志将会发送给/dev/null logfile stdout # 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 # 设置数据库的数量,默认数据库为0,可以使用select <dbid>命令在连接上指定数据库id # dbid是从0到‘databases’-1的数目 databases 16 ################################ SNAPSHOTTING ################################# # 指定在多长时间内,有多少次更新操作,就将数据同步到数据文件,可以多个条件配合 # 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. # # 满足以下条件将会同步数据: # 900秒(15分钟)内有1个更改 # 300秒(5分钟)内有10个更改 # 60秒内有10000个更改 # Note: 可以把所有“save”行注释掉,这样就取消同步操作了 save 900 1 save 300 10 save 60 10000 # 指定存储至本地数据库时是否压缩数据,默认为yes,Redis采用LZF压缩,如果为了节省CPU时间,可以关闭该选项,但会导致数据库文件变的巨大 rdbcompression yes # 指定本地数据库文件名,默认值为dump.rdb dbfilename dump.rdb # 工作目录. # 指定本地数据库存放目录,文件名由上一个dbfilename配置项指定 # # Also the Append Only File will be created inside this directory. # # 注意,这里只能指定一个目录,不能指定文件名 dir ./ ################################# REPLICATION ################################# # 主从复制。使用slaveof从 Redis服务器复制一个Redis实例。注意,该配置仅限于当前slave有效 # so for example it is possible to configure the slave to save the DB with a # different interval, or to listen to another port, and so on. # 设置当本机为slav服务时,设置master服务的ip地址及端口,在Redis启动时,它会自动从master进行数据同步 # slaveof <masterip> <masterport> # 当master服务设置了密码保护时,slav服务连接master的密码 # 下文的“requirepass”配置项可以指定密码 # masterauth <master-password> # When a slave lost the 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 data 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 # 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 a timeout for both Bulk transfer I/O timeout and # master data or ping response timeout. The default value is 60 seconds. # # 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 ################################## SECURITY ################################### # 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. # 设置Redis连接密码,如果配置了连接密码,客户端在连接Redis时需要通过auth <password>命令提供密码,默认关闭 # requirepass foobared # Command renaming. # # It is possilbe to change the name of dangerous commands in a shared # environment. For instance the CONFIG command may be renamed into something # of hard to guess so that it will be still available for internal-use # tools but not available for general clients. # # Example: # # rename-command CONFIG b840fc02d524045429941cc15f59e41cb7be6c52 # # It is also possilbe to completely kill a command renaming it into # an empty string: # # rename-command CONFIG "" ################################### LIMITS #################################### # 设置同一时间最大客户端连接数,默认无限制,Redis可以同时打开的客户端连接数为Redis进程可以打开的最大文件描述符数, # 如果设置maxclients 0,表示不作限制。当客户端连接数到达限制时,Redis会关闭新的连接并向客户端返回max Number of clients reached错误信息 # maxclients 128 # Don't use more memory than the specified amount of bytes. # When the memory limit is reached Redis will try to remove keys with an # EXPIRE set. It will try to start freeing keys that are going to expire # in little time and preserve keys with a longer time to live. # Redis will also try to remove objects from free lists if possible. # # If all this fails, Redis will start to reply with errors to commands # that will use more memory, like SET, LPUSH, and so on, and will continue # to reply to most read-only commands like GET. # # WARNING: maxmemory can be a good idea mainly if you want to use Redis as a # 'state' server or cache, not as a real DB. When Redis is used as a real # database the memory usage will grow over the weeks, it will be obvious if # it is going to use too much memory in the long run, and you'll have the time # to upgrade. With maxmemory after the limit is reached you'll start to get # errors for write operations, and this may even lead to DB inconsistency. # 指定Redis最大内存限制,Redis在启动时会把数据加载到内存中,达到最大内存后,Redis会先尝试清除已到期或即将到期的Key, # 当此方法处理后,仍然到达最大内存设置,将无法再进行写入操作,但仍然可以进行读取操作。 # Redis新的vm机制,会把Key存放内存,Value会存放在swap区 # maxmemory <bytes> # MAXMEMORY POLICY: how Redis will select what to remove when maxmemory # is reached? You can select among five behavior: # # volatile-lru -> remove the key with an expire set using an LRU algorithm # allkeys-lru -> remove any key accordingly 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 all the kind of policies, Redis will return an error on write # operations, when there are not suitable keys for eviction. # # At the date of writing this 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 volatile-lru # LRU and minimal TTL algorithms are not precise algorithms but approximated # algorithms (in order to save memory), so you can select as well the sample # size to check. For instance for default Redis will check three keys and # pick the one that was used less recently, you can change the sample size # using the following configuration directive. # # maxmemory-samples 3 ############################## APPEND ONLY MODE ############################### # # Note that you can have both the async dumps and the append only file if you # like (you have to comment the "save" statements above to disable the dumps). # Still if append only mode is enabled Redis will load the data from the # log file at startup ignoring the dump.rdb file. # 指定是否在每次更新操作后进行日志记录,Redis在默认情况下是异步的把数据写入磁盘,如果不开启,可能会在断电时导致一段时间内的数据丢失。 # 因为redis本身同步数据文件是按上面save条件来同步的,所以有的数据会在一段时间内只存在于内存中。默认为no # IMPORTANT: Check the BGREWRITEAOF to check how to rewrite the append # log file in background when it gets too big. appendonly no # 指定更新日志文件名,默认为appendonly.aof # appendfilename appendonly.aof # The fsync() call tells the Operating System to actually write data on disk # instead to wait 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. # 指定更新日志条件,共有3个可选值: # no:表示等操作系统进行数据缓存同步到磁盘(快) # always:表示每次更新操作后手动调用fsync()将数据写到磁盘(慢,安全) # everysec:表示每秒同步一次(折衷,默认值) 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", that in pratical terms means that it is # possible to lost 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 will growth by the specified percentage. # # This is how it works: Redis remembers the size of the AOF file after the # latest rewrite (or if no rewrite 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 precentage of zero in order to disable the automatic AOF # rewrite feature. auto-aof-rewrite-percentage 100 auto-aof-rewrite-min-size 64mb ################################## 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 1024 ################################ VIRTUAL MEMORY ############################### ### WARNING! Virtual Memory is deprecated in Redis 2.4 ### The use of Virtual Memory is strongly discouraged. ### WARNING! Virtual Memory is deprecated in Redis 2.4 ### The use of Virtual Memory is strongly discouraged. # Virtual Memory allows Redis to work with datasets bigger than the actual # amount of RAM needed to hold the whole dataset in memory. # In order to do so very used keys are taken in memory while the other keys # are swapped into a swap file, similarly to what operating systems do # with memory pages. # 指定是否启用虚拟内存机制,默认值为no, # VM机制将数据分页存放,由Redis将访问量较少的页即冷数据swap到磁盘上,访问多的页面由磁盘自动换出到内存中 # 把vm-enabled设置为yes,根据需要设置好接下来的三个VM参数,就可以启动VM了 vm-enabled no # vm-enabled yes # This is the path of the Redis swap file. As you can guess, swap files # can't be shared by different Redis instances, so make sure to use a swap # file for every redis process you are running. Redis will complain if the # swap file is already in use. # # Redis交换文件最好的存储是SSD(固态硬盘) # 虚拟内存文件路径,默认值为/tmp/redis.swap,不可多个Redis实例共享 # *** WARNING *** if you are using a shared hosting the default of putting # the swap file under /tmp is not secure. Create a dir with access granted # only to Redis user and configure Redis to create the swap file there. vm-swap-file /tmp/redis.swap # With vm-max-memory 0 the system will swap everything it can. Not a good # default, just specify the max amount of RAM you can in bytes, but it's # better to leave some margin. For instance specify an amount of RAM # that's more or less between 60 and 80% of your free RAM. # 将所有大于vm-max-memory的数据存入虚拟内存,无论vm-max-memory设置多少,所有索引数据都是内存存储的(Redis的索引数据就是keys) # 也就是说当vm-max-memory设置为0的时候,其实是所有value都存在于磁盘。默认值为0 vm-max-memory 0 # Redis swap文件分成了很多的page,一个对象可以保存在多个page上面,但一个page上不能被多个对象共享,vm-page-size是要根据存储的数据大小来设定的。 # 建议如果存储很多小对象,page大小最后设置为32或64bytes;如果存储很大的对象,则可以使用更大的page,如果不确定,就使用默认值 vm-page-size 32 # 设置swap文件中的page数量由于页表(一种表示页面空闲或使用的bitmap)是存放在内存中的,在磁盘上每8个pages将消耗1byte的内存 # swap空间总容量为 vm-page-size * vm-pages # # With the default of 32-bytes memory pages and 134217728 pages Redis will # use a 4 GB swap file, that will use 16 MB of RAM for the page table. # # It's better to use the smallest acceptable value for your application, # but the default is large in order to work in most conditions. vm-pages 134217728 # Max number of VM I/O threads running at the same time. # This threads are used to read/write data from/to swap file, since they # also encode and decode objects from disk to memory or the reverse, a bigger # number of threads can help with big objects even if they can't help with # I/O itself as the physical device may not be able to couple with many # reads/writes operations at the same time. # 设置访问swap文件的I/O线程数,最后不要超过机器的核数,如果设置为0,那么所有对swap文件的操作都是串行的,可能会造成比较长时间的延迟,默认值为4 vm-max-threads 4 ############################### ADVANCED CONFIG ############################### # Hashes are encoded in a special way (much more memory efficient) when they # have at max a given numer of elements, and the biggest element does not # exceed a given threshold. You can configure this limits with the following # configuration directives. # 指定在超过一定的数量或者最大的元素超过某一临界值时,采用一种特殊的哈希算法 hash-max-zipmap-entries 512 hash-max-zipmap-value 64 # Similarly to hashes, small lists are also encoded in a special way in order # to save a lot of space. The special representation is only used when # you are under the following limits: list-max-ziplist-entries 512 list-max-ziplist-value 64 # Sets have a special encoding in just one case: when a set is composed # of just strings that happens 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 # 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 an hash table # that is rhashing, 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 # active rehashing 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 form time to time # to queries with 2 milliseconds delay. # 指定是否激活重置哈希,默认为开启 activerehashing yes ################################## INCLUDES ################################### # 指定包含其他的配置文件,可以在同一主机上多个Redis实例之间使用同一份配置文件,而同时各实例又拥有自己的特定配置文件 # include /path/to/local.conf # include /path/to/other.conf
redis.conf内容
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原文链接:https://www.cnblogs.com/chenxuming/p/9682571.html