如何獲取容器的啟動命令

• 容器早已創建好，如何得知它的啟動引數(資料掛載到哪)

#假設通過如下命令啟動了一個容器
docker run  -d  --name mysql_cdh \
-p 3306:3306 \
-e MYSQL_ROOT_PASSWORD=123456 \
-v mysql-data:/var/lib/mysql \
--restart=always \
mysql:5.5 --character-set-server=utf8

#如何通過容器名得知啟動引數
[root@jenkins ~]# docker inspect mysql_cdh
[
    {
        "Id": "3aad772538b5e86705d3358362517a08d53f951aa6522e2881321135f05c8872",
        "Created": "2019-09-25T01:43:37.720505875Z",
        "Path": "docker-entrypoint.sh",
        "Args": [
            "--character-set-server=utf8"
        ],
        ...
        "Name": "/mysql_cdh",
     
	  	"HostConfig": {
	            "Binds": [
	                "mysql-data:/var/lib/mysql"
	            ],
	            ...
	            "NetworkMode": "default",
	            "PortBindings": {
	                "3306/tcp": [
	                    {
	                        "HostIp": "",
	                        "HostPort": "3306"
	                    }
	                ]
	            },
	            "RestartPolicy": {
	                "Name": "always",
	                "MaximumRetryCount": 0
	            },
	
    	"Mounts": [
	            {
	                "Type": "volume",
	                "Name": "mysql-data",
	                "Source": "/var/lib/docker/volumes/mysql-data/_data",
	                "Destination": "/var/lib/mysql",
	                "Driver": "local",
	                "Mode": "z",
	                "RW": true,
	                "Propagation": ""
	            }
	        ],
	
		"Config": {
	            "Hostname": "3aad772538b5",
	             ...
	            "ExposedPorts": {
	                "3306/tcp": {}
	            },
				...
	            "Env": [
	                "MYSQL_ROOT_PASSWORD=123456",
	                "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/local/mysql/bin:/usr/local/mysql/scripts",
	                "GOSU_VERSION=1.7",
	                "MYSQL_MAJOR=5.5",
	                "MYSQL_VERSION=5.5.62"
	            ],
	            "Cmd": [
	                "--character-set-server=utf8"
	            ],

1, 容器層：檔案存放路徑

#1, 啟動容器
[root@master ~]# docker run -d --name nginx2 nginx
a9c9f31cdccf13c3385f3de33443325d2e14d69458e6d679e54c8cf9e5ff24c8

#2, 獲取容器id
[root@master ~]# docker inspect nginx2  | grep -i id 
[root@master ~]# docker inspect nginx2  | grep -i id 
        "Id": "a9c9f31cdccf13c3385f3de33443325d2e14d69458e6d679e54c8cf9e5ff24c8",
            "Pid": 2069,
        "ExecIDs": null,
            "ContainerIDFile": "",
			
#查看容器臨時檔案--每次創建時隨機生成的檔案(容器層)
# /var/lib/docker/containers/容器id
[root@master ~]# docker inspect nginx2  | grep -i path
  "Path": "nginx",
  "ResolvConfPath": "/var/lib/docker/containers/a9c9f31cdccf13c3385f3de33443325d2e14d69458e6d679e54c8cf9e5ff24c8/resolv.conf",
  "HostnamePath": "/var/lib/docker/containers/a9c9f31cdccf13c3385f3de33443325d2e14d69458e6d679e54c8cf9e5ff24c8/hostname",
  "HostsPath": "/var/lib/docker/containers/a9c9f31cdccf13c3385f3de33443325d2e14d69458e6d679e54c8cf9e5ff24c8/hosts",
  "LogPath": "/var/lib/docker/containers/a9c9f31cdccf13c3385f3de33443325d2e14d69458e6d679e54c8cf9e5ff24c8/a9c9f31cdccf13c3385f3de33443325d2e14d69458e6d679e54c8cf9e5ff24c8-json.log",

后天修改容器埠 (要先停止docker服務,否則不生效)

通過容器層檔案，找到組態檔hostconfig.json，修改容器映射的埠

[root@docker a9c9f31cd...ff24c8]# pwd
/var/lib/docker/containers/d93185e3a0....2e544ccfa
[root@docker a9c9f31cd...ff24c8]# cat hostconfig.json 
{"Binds":["/dockersuperset:/home/superset"],"ContainerIDFile":"",
"LogConfig":{"Type":"json-file","Config":{}},"NetworkMode":"default",
"PortBindings":{"8088/tcp":[{"HostIp":"","HostPort":"8099"}]}......

2, 鏡像層：檔案存放路徑

[root@master ~]# docker image inspect nginx |tail  -n 22
        "GraphDriver": {
            "Data": {
                "LowerDir": "/var/lib/docker/overlay2/bf20cf788cc053f00ff1467525d50e19bd1cf07a2167f72511bdfcb28918a472/diff:/var/lib/docker/overlay2/317d80bb7ae58ed288be9ebd84aeb5b4b3a1c06f3211f5d1f32d89b629d1876e/diff",
                "MergedDir": "/var/lib/docker/overlay2/7782d0eb292fdc8bbd73bf9bae2d65468e8aba0bcd6baed55ac348618b80ae16/merged",
                "UpperDir": "/var/lib/docker/overlay2/7782d0eb292fdc8bbd73bf9bae2d65468e8aba0bcd6baed55ac348618b80ae16/diff",
                "WorkDir": "/var/lib/docker/overlay2/7782d0eb292fdc8bbd73bf9bae2d65468e8aba0bcd6baed55ac348618b80ae16/work"
            },
            "Name": "overlay2"
        },

a, 容器層,鏡像層：關聯

I, 子容器：拷貝鏡像的檔案

II, 子容器：添加新檔案

III, 子容器：修改由鏡像拷貝的檔案

b, 在鏡像層(檔案存盤目錄)， 修改組態檔

# 進入鏡容器檔案存盤目錄， 修改組態檔
[root@master d37ff828e6308...0c0599b]# ls diff/run/
nginx.pid
[root@master d37ff828e6308...0c0599b]# ls diff/var/cache/nginx/
client_temp  fastcgi_temp  proxy_temp  scgi_temp  uwsgi_temp

[root@master d37ff828e6308...0c0599b]# ls merged/
bin/        dev/        etc/        lib/        media/      opt/        root/       sbin/       sys/        usr/        
boot/       .dockerenv  home/       lib64/      mnt/        proc/       run/        srv/        tmp/        var/        

[root@master d37ff828e6308...0c0599b]# ls merged/etc/nginx/
conf.d  fastcgi_params  koi-utf  koi-win  mime.types  modules  nginx.conf  scgi_params  uwsgi_params  win-utf

[root@master d37ff828e6308...0c0599b]# head merged/etc/nginx/nginx.conf 
user  nginx;
worker_processes  1;

#在此處修改組態檔，把user nginx; worker_process 1; 這兩行的分號去掉，看容器里面的配置是否更改
[root@master d37ff828e6308...0c0599b]# head merged/etc/nginx/nginx.conf -n 3
user  nginx
worker_processes  1

#登陸容器，查看修改的配置： 驗證是否生效
[root@master d37ff828e6308...0c0599b]# docker exec -it nginx2 bash
root@a9c9f31cdccf:/# head /etc/nginx/nginx.conf -n 3
user  nginx
worker_processes  1

3, 修改默認存盤路徑

a, 重建/var/lib/docker目錄

#備份資料到新的存放路徑
service docker stop
mkdir /docker.bak
mv /var/lib/docker/*  /docker.bak

#創建軟連接
mkdir /home/docker-data
mv /docker.bak/*  /home/docker-data/ && rmdir /docker.bak
ln -s   /home/docker-data  /var/lib/docker

b, 修改配置

vi /usr/lib/systemd/system/docker.service  
ExecStart=/usr/bin/dockerd --graph /new-path/docker 

#reload組態檔 
systemctl daemon-reload 
#重啟docker 
systemctl restart docker.service