非常实用的 Docker 使用技巧
在平时的工作中，docker 接触得很多，除了经常使用的 docker run ，docker stop 等命令，docker 还有很多十分有用但是却不经常使用的命令，下面就来总结一下：
docker top
这个命令是用来查看一个容器里面的进程信息的，比如你想查看一个 nginx 容器里面有几个 nginx 进程的时候，就可以这么做：
[[email protected] ~]# docker top fe2b5a947561
UID PID PPID C STIME TTY TIME CMD
root 2318 2298 0 Oct17 ? 00:00:00 nginx: master process /usr/local/openresty/bin/openresty -g daemon off;
65534 2367 2318 0 Oct17 ? 00:00:04 nginx: worker process
docker load && docker save
我一般使用这两个命令去下载打包docker的镜像，因为国内的网速并不像国外那么快。docker save 可以把一个镜像保存到 tar 文件中，你可以这么做：
[[email protected] ~]# docker save alpine:3.12 >alpine:3.12.tar
[[email protected] ~]# ll
total 5724
-rw-r--r-- 1 root root 5854208 Oct 19 02:23 alpine:3.12.tar
同时 docker load 可以把镜像从 tar 文件导入到 docker 中
[[email protected] ~]# docker load < alpine:3.12.tar
docker search
这个命令可以帮助你在命令行中方便的搜索 DockerHub 中的镜像，比如:
[[email protected] ~]# docker search nginx
NAME DESCRIPTION STARS OFFICIAL AUTOMATED
nginx Official build of Nginx. 13880 [OK]
jwilder/nginx-proxy Automated Nginx reverse proxy for docker con… 1897 [OK]
richarvey/nginx-php-fpm Container running Nginx + PHP-FPM capable of… 791 [OK]
linuxserver/nginx An Nginx container, brought to you by LinuxS… 127
jc21/nginx-proxy-manager Docker container for managing Nginx proxy ho… 98
tiangolo/nginx-rtmp Docker image with Nginx using the nginx-rtmp… 98 [OK]
bitnami/nginx Bitnami nginx Docker Image 89 [OK]
alfg/nginx-rtmp NGINX, nginx-rtmp-module and FFmpeg from sou… 76 [OK]
nginxdemos/hello NGINX webserver that serves a simple page co… 62 [OK]
jlesage/nginx-proxy-manager Docker container for Nginx Proxy Manager 61 [OK]
nginx/nginx-ingress NGINX Ingress Controller for Kubernetes 42
privatebin/nginx-fpm-alpine PrivateBin running on an Nginx, php-fpm & Al… 38 [OK]
nginxinc/nginx-unprivileged Unprivileged NGINX Dockerfiles 19
schmunk42/nginx-redirect A very simple container to redirect HTTP tra… 19 [OK]
nginx/nginx-prometheus-exporter NGINX Prometheus Exporter 15
centos/nginx-112-centos7 Platform for running nginx 1.12 or building … 15
staticfloat/nginx-certbot Opinionated setup for automatic TLS certs lo… 13 [OK]
raulr/nginx-wordpress Nginx front-end for the official wordpress:f… 13 [OK]
centos/nginx-18-centos7 Platform for running nginx 1.8 or building n… 13
sophos/nginx-vts-exporter Simple server that scrapes Nginx vts stats a… 7 [OK]
mailu/nginx Mailu nginx frontend 7 [OK]
flashspys/nginx-static Super Lightweight Nginx Image 6 [OK]
bitnami/nginx-ingress-controller Bitnami Docker Image for NGINX Ingress Contr… 6 [OK]
ansibleplaybookbundle/nginx-apb An APB to deploy NGINX 1 [OK]
wodby/nginx Generic nginx
docker events
这个命令可以帮助你实时获取 docker 的各种事件信息，比如创建了一个容器什么的。
# 参数
-f ：根据条件过滤事件；
--since ：从指定的时间戳后显示所有事件;
--until ：流水时间显示到指定的时间为止；
[[email protected] ~]# docker events --since="1603088994"
2020-10-19T02:30:40.031422094-04:00 container exec_create: /healthcheck.sh 5f5cc61abc206152e2d56a6ffe9429d5eddf846a08ca8db8e78b7de7ee6796f0 (com.docker.compose.config-hash=decd5a094f8090e9da6f072b9b62bf94e850a2ac4480649539e79d74e78938e2, com.docker.compose.container-number=1, com.docker.compose.oneoff=False, com.docker.compose.project=ob, com.docker.compose.project.config_files=docker-compose.yml, com.docker.compose.project.working_dir=/data/scripts/ob, com.docker.compose.service=bitwarden, com.docker.compose.version=1.27.4, execID=51cdd01af59c2bd3ef228f15a2e465ebed02f6918a4ff2fd47287d2ad8fe3f3d, image=bitwardenrs/server, name=bitwardenrs)
2020-10-19T02:30:40.031444660-04:00 container exec_start: /healthcheck.sh 5f5cc61abc206152e2d56a6ffe9429d5eddf846a08ca8db8e78b7de7ee6796f0 (com.docker.compose.config-hash=decd5a094f8090e9da6f072b9b62bf94e850a2ac4480649539e79d74e78938e2, com.docker.compose.container-number=1, com.docker.compose.oneoff=False, com.docker.compose.project=ob, com.docker.compose.project.config_files=docker-compose.yml, com.docker.compose.project.working_dir=/data/scripts/ob, com.docker.compose.service=bitwarden, com.docker.compose.version=1.27.4, execID=51cdd01af59c2bd3ef228f15a2e465ebed02f6918a4ff2fd47287d2ad8fe3f3d, image=bitwardenrs/server, name=bitwardenrs)
2020-10-19T02:30:40.163816870-04:00 container exec_die 5f5cc61abc206152e2d56a6ffe9429d5eddf846a08ca8db8e78b7de7ee6796f0 (com.docker.compose.config-hash=decd5a094f8090e9da6f072b9b62bf94e850a2ac4480649539e79d74e78938e2, com.docker.compose.container-number=1, com.docker.compose.oneoff=False, com.docker.compose.project=ob, com.docker.compose.project.config_files=docker-compose.yml, com.docker.compose.project.working_dir=/data/scripts/ob, com.docker.compose.service=bitwarden, com.docker.compose.version=1.27.4, execID=51cdd01af59c2bd3ef228f15a2e465ebed02f6918a4ff2fd47287d2ad8fe3f3d, exitCode=0, image=bitwardenrs/server, name=bitwardenrs)
docker update
当你 docker run 了之后却发现里面有一些参数并不是你想要的状态比如你设置的 nginx 容器 cpu 或者内存太小，这个时候你就可以使用 docker update 去修改这些参数。
[[email protected] ~]# docker update ob_nginx_1 --cpus 2
docker history
当你修改了一个镜像，但是忘记了每一层的修改命令，或者你想查看一个镜像是怎么构建的时候就可以使用这个命令，比如：
[[email protected] ~]# docker history e1152e363593
IMAGE CREATED CREATED BY SIZE COMMENT
e1152e363593 42 hours ago /bin/sh -c #(nop) STOPSIGNAL SIGQUIT 0B
f89149214392 42 hours ago /bin/sh -c #(nop) CMD ["/usr/local/openrest… 0B
b5fd45b3c8ae 42 hours ago /bin/sh -c #(nop) COPY file:290b28dbe3f8ab14… 1.59kB
d13cc0fd71da 42 hours ago /bin/sh -c #(nop) COPY file:476e52e5e1cbf47e… 1.84kB
1f0fa4277a71 42 hours ago /bin/sh -c #(nop) ENV PATH=/usr/local/sbin:… 0B
7f25882884ce 42 hours ago |16 RESTY_ADD_PACKAGE_BUILDDEPS= RESTY_ADD_P… 104MB
9901f3176c82 43 hours ago /bin/sh -c #(nop) LABEL resty_eval_post_mak… 0B
a8deba2782a5 43 hours ago /bin/sh -c #(nop) LABEL resty_eval_pre_conf… 0B
a5ff733dfa4d 43 hours ago /bin/sh -c #(nop) LABEL resty_add_package_r… 0B
85b0786abdcb 43 hours ago /bin/sh -c #(nop) LABEL resty_add_package_b… 0B
be9af64aed24 43 hours ago /bin/sh -c #(nop) LABEL resty_config_deps=-… 0B
845cbb98c926 43 hours ago /bin/sh -c #(nop) LABEL resty_config_option… 0B
de15adc5fa00 43 hours ago /bin/sh -c #(nop) LABEL resty_config_option… 0B
docker wait
这个命令可以查看容器的退出状态，比如：
[[email protected] ~]# docker wait fe2b5a947561
这样你就可以知道这个容器是正常退出的还是异常退出的了。
docker pause && docker unpause
当你运行了一个容器但是想要暂停它运行的时候，你就可以使用这个命令。
[[email protected] ~]# docker pause fe2b5a947561
docker diff
当你运行了一个容器，但是你不知道容器里修改了哪一些文件的时候可以使用这个命令，比如：
[[email protected] ~]# docker diff fe2b5a947561
C /usr
C /usr/local
C /usr/local/openresty
C /usr/local/openresty/nginx
A /usr/local/openresty/nginx/proxy_temp
A /usr/local/openresty/nginx/proxy_temp/0
A /usr/local/openresty/nginx/proxy_temp/0/01
A /usr/local/openresty/nginx/proxy_temp/0/02
A /usr/local/openresty/nginx/proxy_temp/1
A /usr/local/openresty/nginx/proxy_temp/1/01
A /usr/local/openresty/nginx/proxy_temp/1/02
docker stats
这个是 docker 内置的监控命令，当你想要查看当前主机下所有容器占用内存和 cpu 的情况的时候就可以使用这个命令。
[[email protected] ~]# docker stats
CONTAINER ID NAME CPU % MEM USAGE / LIMIT MEM % NET I/O BLOCK I/O PIDS
fe2b5a947561 ob_nginx_1 0.00% 26.41MiB / 991.1MiB 2.66% 69.6MB / 18.9MB 0B / 0B 2
参考资料：民工哥技术之路
