Containerd的高级命令行工具nerdctl
作者：互联网
Containerd的高级命令行工具nerdctl
安装
我们要在GitHub Release页面上下载对应的压缩包解压到PATH路径下：
# 如果没有安装 containerd，则可以下载 nerdctl-full-<VERSION>-linux-amd64.tar.gz 包进行安装
wget https://github.com/containerd/nerdctl/releases/download/v0.12.1/nerdctl-0.12.1-linux-amd64.tar.gz
# 如果有限制，也可以替换成下面的 URL 加速下载
# wget https://download.fastgit.org/containerd/nerdctl/releases/download/v0.12.1/nerdctl-0.12.1-linux-amd64.tar.gz
mkdir -p /usr/local/containerd/bin/ && tar -zxvf nerdctl-0.12.1-linux-amd64.tar.gz nerdctl && mv nerdctl /usr/local/containerd/bin/
ln -s /usr/local/containerd/bin/nerdctl /usr/local/bin/nerdctl
nerdctl version
Client:
Version: v0.12.1
Git commit: c802f934791f83dacf20a041cd1c865f8fac954e
Server:
containerd:
Version: v1.5.5
Revision: 72cec4be58a9eb6b2910f5d10f1c01ca47d231c0
命令
nerdctl run
nerdctl run 和docker run的运行容器命令类似，例如：
nerdctl run -d -p 80:80 --name=nginx --restart=always nginx:alpine
docker.io/library/nginx:alpine: resolved |++++++++++++++++++++++++++++++++++++++|
index-sha256:bead42240255ae1485653a956ef41c9e458eb077fcb6dc664cbc3aa9701a05ce: done |++++++++++++++++++++++++++++++++++++++| manifest-sha256:ce6ca11a3fa7e0e6b44813901e3289212fc2f327ee8b1366176666e8fb470f24: done |++++++++++++++++++++++++++++++++++++++| config-sha256:7ce0143dee376bfd2937b499a46fb110bda3c629c195b84b1cf6e19be1a9e23b: done |++++++++++++++++++++++++++++++++++++++| elapsed: 5.3 s total: 3.1 Ki (606.0 B/s) 6e489777d2f73dda8a310cdf8da9df38353c1aa2021d3c2270b30eff1806bcf8
可选的参数使用和 docker run 基本一直，比如 -i、-t、--cpus、--memory 等选项，可以使用 nerdctl run --help 获取可使用的命令选项：
nerdctl run --help
NAME:
nerdctl run - Run a command in a new container
USAGE:
nerdctl run [command options] [arguments...]
OPTIONS:
--help show help (default: false)
--tty, -t (Currently -t needs to correspond to -i) (default: false)
--interactive, -i Keep STDIN open even if not attached (default: false)
--detach, -d Run container in background and print container ID (default: false)
--restart value Restart policy to apply when a container exits (implemented values: "no"|"always") (default: "no")
--rm Automatically remove the container when it exits (default: false)
--pull value Pull image before running ("always"|"missing"|"never") (default: "missing")
--network value, --net value Connect a container to a network ("bridge"|"host"|"none") (default: "bridge")
--dns value Set custom DNS servers (default: "8.8.8.8", "1.1.1.1")
--publish value, -p value Publish a container's port(s) to the host
--hostname value, -h value Container host name
--cpus value Number of CPUs (default: 0)
--memory value, -m value Memory limit
--pid value PID namespace to use
--pids-limit value Tune container pids limit (set -1 for unlimited) (default: -1)
--cgroupns value Cgroup namespace to use, the default depends on the cgroup version ("host"|"private") (default: "host")
--cpuset-cpus value CPUs in which to allow execution (0-3, 0,1)
--cpu-shares value CPU shares (relative weight) (default: 0)
--device value Add a host device to the container
--user value, -u value Username or UID (format: <name|uid>[:<group|gid>])
--security-opt value Security options
--cap-add value Add Linux capabilities
--cap-drop value Drop Linux capabilities
--privileged Give extended privileges to this container (default: false)
--runtime value Runtime to use for this container, e.g. "crun", or "io.containerd.runsc.v1" (default: "io.containerd.runc.v2")
--sysctl value Sysctl options
--gpus value GPU devices to add to the container ('all' to pass all GPUs)
--volume value, -v value Bind mount a volume
--read-only Mount the container's root filesystem as read only (default: false)
--rootfs The first argument is not an image but the rootfs to the exploded container (default: false)
--entrypoint value Overwrite the default ENTRYPOINT of the image
--workdir value, -w value Working directory inside the container
--env value, -e value Set environment variables
--env-file value Set environment variables from file
--name value Assign a name to the container
--label value, -l value Set meta data on a container
--label-file value Read in a line delimited file of labels
--cidfile value Write the container ID to the file
--shm-size value Size of /dev/shm
nerctl exec
同样也可以使用 exec 命令执行容器相关命令，例如：
nerdctl exec -it nginx /bin/sh
/ # date
Thu Aug 19 06:43:19 UTC 2021
/ #
容器管理
nerdctl ps: 列出容器
使用nerdctl ps命令可以列出所有容器。
nerdctl ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
6e489777d2f7 docker.io/library/nginx:alpine "/docker-entrypoint.…" 10 minutes ago Up 0.0.0.0:80->80/tcp nginx
同样可以使用 -a 选项显示所有的容器列表，默认只显示正在运行的容器，不过需要注意的是 nerdctl ps 命令并没有实现 docker ps 下面的 --filter、--format、--last、--size 等选项。
nerctl inspect
获取容器的详细信息。基本上与docker inspect一致
nerdctl inspect nginx
[
{
"Id": "6e489777d2f73dda8a310cdf8da9df38353c1aa2021d3c2270b30eff1806bcf8",
"Created": "2021-08-19T06:35:46.403464674Z",
"Path": "/docker-entrypoint.sh",
"Args": [
"nginx",
"-g",
"daemon off;"
],
"State": {
"Status": "running",
"Running": true,
"Paused": false,
"Pid": 2002,
"ExitCode": 0,
"FinishedAt": "0001-01-01T00:00:00Z"
},
"Image": "docker.io/library/nginx:alpine",
"ResolvConfPath": "/var/lib/nerdctl/1935db59/containers/default/6e489777d2f73dda8a310cdf8da9df38353c1aa2021d3c2270b30eff1806bcf8/resolv.conf",
"LogPath": "/var/lib/nerdctl/1935db59/containers/default/6e489777d2f73dda8a310cdf8da9df38353c1aa2021d3c2270b30eff1806bcf8/6e489777d2f73dda8a310cdf8da9df38353c1aa2021d3c2270b30eff1806bcf8-json.log",
"Name": "nginx",
"Driver": "overlayfs",
"Platform": "linux",
"AppArmorProfile": "nerdctl-default",
"NetworkSettings": {
"Ports": {
"80/tcp": [
{
"HostIp": "0.0.0.0",
"HostPort": "80"
}
]
},
"GlobalIPv6Address": "",
"GlobalIPv6PrefixLen": 0,
"IPAddress": "10.4.0.3",
"IPPrefixLen": 24,
"MacAddress": "f2:b1:8e:a2:fe:18",
"Networks": {
"unknown-eth0": {
"IPAddress": "10.4.0.3",
"IPPrefixLen": 24,
"GlobalIPv6Address": "",
"GlobalIPv6PrefixLen": 0,
"MacAddress": "f2:b1:8e:a2:fe:18"
}
}
}
}
]
nerdctl logs
获取容器日志
nerdctl logs -f nginx
......
2021/08/19 06:35:46 [notice] 1#1: start worker processes
2021/08/19 06:35:46 [notice] 1#1: start worker process 32
2021/08/19 06:35:46 [notice] 1#1: start worker process 33
支持 -f、-t、-n、--since、--until 这些选项。
nerdctl rm
删除容器
nerdctl rm nginx
You cannot remove a running container f4ac170235595f28bf962bad68aa81b20fc83b741751e7f3355bd77d8016462d. Stop the container before attempting removal or force remove
nerdctl rm -f ginx
nginx
nerdctl ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
要强制删除同样可以使用 -f 或 --force 选项来操作。
镜像管理
nerdctl images： 查看镜像列表
nerdctl images
REPOSITORY TAG IMAGE ID CREATED SIZE
alpine latest eb3e4e175ba6 6 days ago 5.9 MiB
nginx alpine bead42240255 29 minutes ago 16.0 KiB
也需要注意的是没有实现 docker images 的一些选项，比如 --all、--digests、--filter、--format。
nerdctl pull: 拉取镜像
docker.io/library/busybox:latest:
resolved |++++++++++++++++++++++++++++++++++++++|
index-sha256:0f354ec1728d9ff32edcd7d1b8bbdfc798277ad36120dc3dc683be44524c8b60: done |++++++++++++++++++++++++++++++++++++++| manifest-sha256:dca71257cd2e72840a21f0323234bb2e33fea6d949fa0f21c5102146f583486b: done |++++++++++++++++++++++++++++++++++++++| config-sha256:69593048aa3acfee0f75f20b77acb549de2472063053f6730c4091b53f2dfb02: done |++++++++++++++++++++++++++++++++++++++| layer-sha256:b71f96345d44b237decc0c2d6c2f9ad0d17fde83dad7579608f1f0764d9686f2: done |++++++++++++++++++++++++++++++++++++++| elapsed: 5.9 s total: 752.8 (127.5 KiB/s)
nerdctl push：推送镜像
当然在推送镜像之前也可以使用 nerdctl login 命令登录到镜像仓库，然后再执行 push 操作。
可以使用 nerdctl login --username xxx --password xxx 进行登录，使用 nerdctl logout 可以注销退出登录。
nerdctl tag：镜像标签
使用 tag 命令可以为一个镜像创建一个别名镜像：
nerdctl images
REPOSITORY TAG IMAGE ID CREATED SIZE
busybox latest 0f354ec1728d 6 minutes ago 1.3 MiB
nginx alpine bead42240255 41 minutes ago 16.0 KiB
nerdctl tag nginx:alpine harbor.k8s.local/course/nginx:alpine
nerdctl images
REPOSITORY TAG IMAGE ID CREATED SIZE
busybox latest 0f354ec1728d 7 minutes ago 1.3 MiB
nginx alpine bead42240255 41 minutes ago 16.0 KiB
harbor.k8s.local/course/nginx alpine bead42240255 2 seconds ago 16.0 KiB
nerdctl save：导出镜像
使用 save 命令可以导出镜像为一个 tar 压缩包。
nerdctl save -o busybox.tar.gz busybox:latest
ls -lh busybox.tar.gz
-rw-r--r-- 1 root root 761K Aug 19 15:19 busybox.tar.gz
nerdctl rmi：删除镜像
nerdctl rmi busybox
Untagged: docker.io/library/busybox:latest@sha256:0f354ec1728d9ff32edcd7d1b8bbdfc798277ad36120dc3dc683be44524c8b60
Deleted: sha256:5b8c72934dfc08c7d2bd707e93197550f06c0751023dabb3a045b723c5e7b373
nerdctl load：导入镜像
使用 load 命令可以将上面导出的镜像再次导入：
nerdctl load -i busybox.tar.gz
unpacking docker.io/library/busybox:latest (sha256:0f354ec1728d9ff32edcd7d1b8bbdfc798277ad36120dc3dc683be44524c8b60)...done
使用 -i 或 --input 选项指定需要导入的压缩包。
镜像构建
镜像构建是平时我们非常重要的一个需求，我们知道 ctr 并没有构建镜像的命令，而现在我们又不使用 Docker 了，那么如何进行镜像构建了，幸运的是 nerdctl 就提供了 nerdctl build 这样的镜像构建命令。
nerdctl build：从Dockerfile构建镜像
比如现在我们定制一个 nginx 镜像，新建一个如下所示的 Dockerfile 文件：
FROM nginx
RUN echo 'Hello Nerdctl From Containerd' > /usr/share/nginx/html/index.html
然后在文件所在目录执行镜像构建命令：
nerdctl build -t nginx:nerdctl -f Dockerfile .
FATA[0000] `buildctl` needs to be installed and `buildkitd` needs to be running, see https://github.com/moby/buildkit: exec: "buildctl": executable file not found in $PATH
可以看到有一个错误提示，需要我们安装 buildctl 并运行 buildkitd，这是因为 nerdctl build 需要依赖 buildkit 工具。
buildkit 项目也是 Docker 公司开源的一个构建工具包，支持 OCI 标准的镜像构建。它主要包含以下部分:
- 服务端
buildkitd：当前支持 runc 和 containerd 作为 worker，默认是 runc，我们这里使用 containerd - 客户端
buildctl：负责解析 Dockerfile，并向服务端 buildkitd 发出构建请求
buildkit 是典型的 C/S 架构，客户端和服务端是可以不在一台服务器上，而 nerdctl 在构建镜像的时候也作为 buildkitd 的客户端，所以需要我们安装并运行 buildkitd。
所以接下来我们先来安装 buildkit：
wget https://github.com/moby/buildkit/releases/download/v0.9.1/buildkit-v0.9.1.linux-amd64.tar.gz
# 如果有限制，也可以替换成下面的 URL 加速下载
# wget https://download.fastgit.org/moby/buildkit/releases/download/v0.9.1/buildkit-v0.9.1.linux-amd64.tar.gz
tar -zxvf buildkit-v0.9.1.linux-amd64.tar.gz -C /usr/local/containerd/
bin/
bin/buildctl
bin/buildkit-qemu-aarch64
bin/buildkit-qemu-arm
bin/buildkit-qemu-i386
bin/buildkit-qemu-mips64
bin/buildkit-qemu-mips64el
bin/buildkit-qemu-ppc64le
bin/buildkit-qemu-riscv64
bin/buildkit-qemu-s390x
bin/buildkit-runc
bin/buildkitd
ln -s /usr/local/containerd/bin/buildkitd /usr/local/bin/buildkitd
ln -s /usr/local/containerd/bin/buildctl /usr/local/bin/buildctl
这里我们使用 Systemd 来管理 buildkitd，创建如下所示的 systemd unit 文件：
cat /etc/systemd/system/buildkit.service
[Unit]
Description=BuildKit
Documentation=https://github.com/moby/buildkit
[Service]
ExecStart=/usr/local/bin/buildkitd --oci-worker=false --containerd-worker=true
[Install]
WantedBy=multi-user.target
然后启动 buildkitd：
systemctl daemon-reload
systemctl enable buildkit --now
Created symlink /etc/systemd/system/multi-user.target.wants/buildkit.service → /etc/systemd/system/buildkit.service.
systemctl status buildkit
● buildkit.service - BuildKit
Loaded: loaded (/etc/systemd/system/buildkit.service; enabled; vendor preset: enabled)
Memory: 8.6M
CGroup: /system.slice/buildkit.service
└─5779 /usr/local/bin/buildkitd --oci-worker=false --containerd-worker=true
Aug 19 16:03:10 ydzsio systemd[1]: Started BuildKit.
Aug 19 16:03:10 ydzsio buildkitd[5779]: time="2021-08-19T16:03:10+08:00" level=warning msg="using host network as the default"
Aug 19 16:03:10 ydzsio buildkitd[5779]: time="2021-08-19T16:03:10+08:00" level=info msg="found worker \"euznuelxhxb689bc5of7pxmbc\", labels>
Aug 19 16:03:10 ydzsio buildkitd[5779]: time="2021-08-19T16:03:10+08:00" level=info msg="found 1 workers, default=\"euznuelxhxb689bc5of7pxm>
Aug 19 16:03:10 ydzsio buildkitd[5779]: time="2021-08-19T16:03:10+08:00" level=warning msg="currently, only the default worker can be used."
Aug 19 16:03:10 ydzsio buildkitd[5779]: time="2021-08-19T16:03:10+08:00" level=info msg="running server on /run/buildkit/buildkitd.sock"
~
现在我们再来重新构建镜像：
构建完成后查看镜像是否构建成功：
nerdctl images
WARN[0000] unparsable image name "overlayfs@sha256:d5b9b9e4c930f30340650cb373f62f97c93ee3b92c83f01c6e00b7b87d62c624"
REPOSITORY TAG IMAGE ID CREATED SIZE
nginx latest 4d4d96ac750a 4 minutes ago 16.0 KiB
nginx nerdctl d5b9b9e4c930 About a minute ago 24.0 KiB
我们可以看到已经有我们构建的 nginx:nerdctl 镜像了。接下来使用上面我们构建的镜像来启动一个容器进行测试：
nerdctl run -d -p 80:80 --name=nginx --restart=always nginx:nerdctl
f8f639cb667926023231b13584226b2c7b856847e0a25bd5f686b9a6e7e3cacd
nerdctl ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
f8f639cb6679 docker.io/library/nginx:nerdctl "/docker-entrypoint.…" 1 second ago Up 0.0.0.0:80->80/tcp nginx
curl localhost
This is a nerdctl build's nginx image base on containerd
这样我们就使用 nerdctl + buildkitd 轻松完成了容器镜像的构建。
当然如果你还想在单机环境下使用 Docker Compose，在 containerd 模式下，我们也可以使用 nerdctl 来兼容该功能。同样我们可以使用 nerdctl compose、nerdctl compose up、nerdctl compose logs、nerdctl compose build、nerdctl compose down 等命令来管理 Compose 服务。这样使用 containerd、nerdctl 结合 buildkit 等工具就完全可以替代 docker 在镜像构建、镜像容器方面的管理功能了。
标签：--,Containerd,value,nerdctl,nginx,buildkit,命令行,镜像 来源： https://www.cnblogs.com/l-uz/p/16519631.html