从零开始的Docker [ 7 ] --- 顶级 Volumes，数据卷， 系统限制sysctls

容器技术 Docker 应用

1. Dockerfile  # 1 年内 肯定生产上会使用 90%
   FROM   alpine  # 构建自己镜像的一基础镜像
   LABEL  key1=value1    # 给镜像添加元数据信息的
   ADD    src    dist   # 把宿主机的文件，复制到镜像中，并且支持直接解压
   COPY   src    dist    通上，但是不支持自动解压，官方推荐
   WORKDIR dir  # 指定了再构建镜像的时候的工作目录（切换执行命令时的当前目录）
   USER  user_name   # 是指定了在构建镜像过程中执行指令的用户，用户必须存在
   HEALTHCHECK test CMD 健康检查的 shell 命令  # 用于检查容器内部服务是否健康
   ONBUILD  COPY  .  /  # 当其他镜像以 此镜像作为基础镜像时，所要执行的命令
   ENTRYPOINT   /docker-entrypoint.sh   # 执行运行容器时候的默认命令，
                                     # 不会被覆盖掉
   CMD # 执行运行容器时候的默认命令或者参数，会被运行容器时候的命令覆盖掉

    # ENTRYPOINT  CMD


2. docker compose  生产上使用率 40%

docker-compose 单机容器编排工具，不能跨主机

k8s 多机集群的容器编排工具，可以跨主机

docker-compose.yml
属性：
version: "3" # 版本号，不用的版本支持不同的属性
services:
  redis:  # 声明的服务名，本质上是一个容器
    image: redis:alpine
    # build: ./dir   # 指定了构建镜像的 Dockerfile 目录所在的位置
    ports:
      - "6379:6379"  # 宿主机端口:容器端口
    command: redis-server  # 执行的默认命令，一般不需要
    environment:
       key1: value1
       KEY2: value2
    healthcheck:
       test:  CMD  redis-cli  ping && echo 0 || echo 1
       interval: 3s
       timeout: 4s
       retries: 3
    networks:
      - net1
      - net2

networks:
   net1:
   net2:

一、顶级 Volumes

映射本地目录到容器目录下

1.配置

[root@Docker ~]# mkdir volumes
[root@Docker ~]# cd volumes/
[root@Docker volumes]# vim docker-compose.yml
[root@Docker volumes]# cat docker-compose.yml
version: "3.8"
services:
  web1:
   image: nginx
   volumes:
     - type: bind # bind volume tmpfile
       source: /root/volumes/nginx/index.html
       target: /usr/share/nginx/html/index.html
     - type: bind
       source: ./nginx/conf/default.conf
       target: /etc/nginx/conf.d/default.conf

[root@Docker volumes]# mkdir -p nginx/conf
[root@Docker volumes]# vim nginx/index.html
[root@Docker volumes]# cat nginx/index.html
Hello Neko

[root@Docker volumes]# ls
docker-compose.yml  nginx

[root@Docker volumes]# docker ps -a
CONTAINER ID   IMAGE            COMMAND                  CREATED      STATUS                    PORTS     NAMES
78a5ad12a07d   nginx            "/docker-entrypoint.…"   2 days ago   Exited (0) 2 days ago               healthcheck_web1_1
[root@Docker volumes]# docker start 78a5ad12a07d
78a5ad12a07d
[root@Docker volumes]# docker cp 78a5ad12a07d:/etc/nginx/conf.d/default.conf .
[root@Docker volumes]# mv default.conf nginx/conf/
[root@Docker volumes]# vim nginx/conf/default.conf 
server {
    
    
    listen       8000;
    server_name  localhost;

    #charset koi8-r;
    #access_log  /var/log/nginx/host.access.log  main;

...

2.启动

[root@Docker volumes]# docker-compose up -d
Creating volumes_web1_1 ... done
[root@Docker volumes]# docker-compose ps 

     Name                   Command               State   Ports 
----------------------------------------------------------------

volumes_web1_1   /docker-entrypoint.sh ngin ...   Up      80/tcp


[root@Docker volumes]# docker-compose exec web1 bash
root@146364e0c842:/# curl 127.0.0.1:8000
Hello Neko

二、数据卷 挂载

1.配置

[root@Docker volumes]# docker-compose down -v
Stopping volumes_web1_1 ... done
Removing 0087e4120800_volumes_db_1 ... done
Removing volumes_web1_1            ... done
Removing network volumes_default
Removing volume volumes_mysql-data
[root@Docker volumes]# vim docker-compose.yml 
[root@Docker volumes]# cat docker-compose.yml 
version: "3.8"
services:
  web1:
   image: nginx
   volumes:
     - type: bind # bind volume tmpfile
       source: /root/volumes/nginx/index.html
       target: /usr/share/nignx/html/index.html
     - type: bind
       source: ./nginx/conf/default.conf
       target: /etc/nginx/conf.d/default.conf
  db:
   image: mysql
   environment:
     MYSQL_ROOT_PASSWORD: Neko@123
   volumes:
     - type: volume
       source: mysql-data # 只写定义过的数据卷名称
       target: /var/lib/mysql/
volumes:

  # 和定义networks 一样的格式，必须是字典格式

  mysql-data: 

2.启动

[root@Docker volumes]# docker-compose up -d
Creating network "volumes_default" with the default driver
Creating volume "volumes_mysql-data" with default driver
Creating volumes_web1_1 ... done
Creating volumes_db_1   ... done

[root@Docker volumes]# docker-compose ps

     Name                   Command               State          Ports       
-----------------------------------------------------------------------------

volumes_db_1     docker-entrypoint.sh mysqld      Up      3306/tcp, 33060/tcp
volumes_web1_1   /docker-entrypoint.sh ngin ...   Up      80/tcp   

[root@Docker volumes]# docker volume ls
DRIVER    VOLUME NAME
local     3fbd8f6afdcec11c486019c513121b26ed42334caf0b0e3c762a8bc6c0d88770
local     11d025419296b8ccaeae67385113b46b9230edbb1fb8624b0134b7b22017be6f
local     76b78a5277539b9ada1f16033975cb7a0d8829cef541b1ff5b2ad314f34b9ce8
local     82f4291404beeef9e51e9cb7e3605d2771777a4cedf5cf17b6d06513bd66be83
local     900449a326af023045ef9fa89e3dd6874ca7bf464f6ed0b69862a84938f75ef4
local     aca694cb2beebfbc9af251586277f1bc69c378aa0d399e7af5047873b39eba0b
local     d79295e6910700a3fc4bd99137d3f57a5c13dfe27e0a819a312651cb8d1ff58d
local     mysql-data
local     neko_vol
local     volumes_mysql-data

三、系统限制 sysctls

1.配置

[root@Docker ~]# mkdir sysctls-ulimits
[root@Docker ~]# cd sysctls-ulimits/
[root@Docker sysctls-ulimits]# vim docker-compose.yml
[root@Docker sysctls-ulimits]# cat docker-compose.yml
version: "3.8"
services:
  web1:
    image: centos
    stdin_open: true
    tty: true
    sysctls:  # 凡是之前通过 sysctl -w 设置的参数都可以在此设置
      net.core.somaxconn: 1024
    ulimits:
      nproc: 65535
      nofile:
        soft: 20000
        hard: 40000

2.启动

[root@Docker sysctls-ulimits]# docker-compose up -d
Creating network "sysctls-ulimits_default" with the default driver
Creating sysctls-ulimits_web1_1 ... done
[root@Docker sysctls-ulimits]# docker-compose ps

         Name             Command    State   Ports
--------------------------------------------------

sysctls-ulimits_web1_1   /bin/bash   Up           
[root@Docker sysctls-ulimits]# docker-compose exec web1 bash
[root@a59d34556450 /]# ulimit -a
core file size          (blocks, -c) unlimited
data seg size           (kbytes, -d) unlimited
scheduling priority             (-e) 0
file size               (blocks, -f) unlimited
pending signals                 (-i) 11216
max locked memory       (kbytes, -l) 64
max memory size         (kbytes, -m) unlimited
open files                      (-n) 20000
pipe size            (512 bytes, -p) 8
POSIX message queues     (bytes, -q) 819200
real-time priority              (-r) 0
stack size              (kbytes, -s) 8192
cpu time               (seconds, -t) unlimited
max user processes              (-u) 65535
virtual memory          (kbytes, -v) unlimited
file locks                      (-x) unlimited