容器运行时Containerd基础

2023-10-03 10:48:46

本文目录：

一、安装Containerd

二、运行一个busybox镜像

三、创建CNI网络

四、使containerd容器具备网络功能

五、与宿主机共享目录

六、与其它容器共享ns

七、docker/containerd并用

一、安装Containerd

本地安装Containerd：

yum install -y yum-utilsyum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repoyum install -y containerd epel-releaseyum install -y jq

systemctl start containerd.service  #启动服务

systemctl enable containerd.service #开启开机自启

Containerd版本：

Client:
  Version:  1.4.4
  Revision: 05f951a3781f4f2c1911b05e61c160e9c30eaa8e
  Go version: go1.13.15

Server:
  Version:  1.4.4
  Revision: 05f951a3781f4f2c1911b05e61c160e9c30eaa8e
  UUID: a05c75f2-6e54-44fa-9418-6dd67d6c635b

初始化Containerd配置：

containerd config default > /etc/containerd/config.tomlsystemctl enabled containerdsystemctl start containerd

替换 containerd 默认的sand_box镜像，编辑/etc/containerd/config.toml文件：

# registry.cn-hangzhou.aliyuncs.com/google-containers/pause-amd64:3.0 可以使用阿里云镜像源sandbox_image = "172.16.0.4/captain/pause-amd64:3.0"

应用配置并重新运行containerd服务

systemctl daemon-reloadsystemctl restart containerd

二、运行一个busybox镜像：

预先准备：

[root@containerd ~]# # 拉取镜像[root@containerd ~]# ctr -n k8s.io i pull docker.io/library/busybox:latest[root@containerd ~]# # 创建一个container(此时还未运行)[root@containerd ~]# ctr -n k8s.io container create docker.io/library/busybox:latest busybox[root@containerd ~]# # 创建一个task[root@containerd ~]# ctr -n k8s.io task start -d busybox[root@containerd ~]# # 上述步骤也可以简写成如下[root@containerd ~]# # ctr -n k8s.io run -d docker.io/library/busybox:latest busybox

查看该容器在宿主机的PID：

[root@containerd ~]# ctr -n k8s.io task lsTASK       PID     STATUS    busybox    2356    RUNNING[root@containerd ~]# ps ajxf|grep "containerd-shim-runc\|2356"|grep -v grep     1   2336   2336   1178 ?            -1 Sl       0   0:00 /usr/bin/containerd-shim-runc-v2 -namespace k8s.io -id busybox -address /run/containerd/containerd.sock  2336   2356   2356   2356 ?            -1 Ss       0   0:00  \_ sh

进入容器：

[root@containerd ~]# ctr -n k8s.io t exec --exec-id $RANDOM -t busybox sh
/ # uname -a
Linux containerd 3.10.0-1062.el7.x86_64 #1 SMP Wed Aug 7 18:08:02 UTC 2019 x86_64 GNU/Linux
/ # ls /etc
group      localtime  network    passwd     shadow
/ # ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
/ #

发送SIGKILL信号量杀死该容器：

[root@containerd ~]# ctr -n k8s.io t kill -s SIGKILL busybox[root@containerd ~]# ctr -n k8s.io t rm busyboxWARN[0000] task busybox exit with non-zero exit code 137

三、创建CNI网络

访问如下两个Git项目，并从release页面下载最新版本:

链接	说明
containernetworking/plugins	CNI插件源码（本教程版本：v0.9.0）文件名：cni-plugins-linux-amd64-v0.9.1.tgz
containernetworking/cni	CNI源码（本教程版本：v0.8.0）文件名：cni-v0.8.0.tar.gz
https://www.cni.dev/plugins/	CNI插件列表介绍文档

下载至HOME目录并解压：

[root@containerd ~]# pwd/root[root@containerd ~]# # 解压至HOME目录的cni-plugins/文件夹中[root@containerd ~]# mkdir -p cni-plugins[root@containerd ~]# tar xvf cni-plugins-linux-amd64-v0.9.0.tgz -C cni-plugins[root@containerd ~]# # 解压至HOME目录的cni/文件夹中[root@containerd ~]# tar -zxvf cni-v0.8.0.tar.gz[root@containerd ~]# mv cni-0.8.0 cni

本教程我们首先使用bridge插件创建一个网卡，首先执行如下指令：

mkdir -p /etc/cni/net.dcat >/etc/cni/net.d/10-mynet.conf <<EOF{  "cniVersion": "0.2.0",  "name": "mynet",  "type": "bridge",  "bridge": "cni0",  "isGateway": true,  "ipMasq": true,  "ipam": {    "type": "host-local",    "subnet": "10.22.0.0/16",    "routes": [      { "dst": "0.0.0.0/0" }    ]  }}EOF
cat >/etc/cni/net.d/99-loopback.conf <<EOF{  "cniVersion": "0.2.0",  "name": "lo",  "type": "loopback"}EOF

随后激活网卡（说明：宿主机执行ip a命令即可看到一个cni0的网卡）：

[root@containerd ~]# cd cni/scripts/[root@containerd scripts]# CNI_PATH=/root/cni-plugins ./priv-net-run.sh echo "Hello World"Hello World[root@containerd scripts]# ip a1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00    inet 127.0.0.1/8 scope host lo       valid_lft forever preferred_lft forever    inet6 ::1/128 scope host        valid_lft forever preferred_lft forever2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000    link/ether 00:0c:29:ea:35:42 brd ff:ff:ff:ff:ff:ff    inet 192.168.105.110/24 brd 192.168.105.255 scope global noprefixroute ens33       valid_lft forever preferred_lft forever    inet6 fe80::1c94:5385:5133:cd48/64 scope link noprefixroute        valid_lft forever preferred_lft forever10: cni0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default qlen 1000    link/ether de:12:0b:ea:a4:bc brd ff:ff:ff:ff:ff:ff    inet 10.22.0.1/24 brd 10.22.0.255 scope global cni0       valid_lft forever preferred_lft forever    inet6 fe80::dc12:bff:feea:a4bc/64 scope link        valid_lft forever preferred_lft forever

四、使containerd容器具备网络功能

注重细节的我们在步骤二中将会发现，busybox容器此刻仅有一张本地网卡，其是无法访问任何网络的，那么我们如何使其具备各容器互通、外部网络通信功能呢？不妨执行如下指令：

[root@containerd ~]# ctr -n k8s.io t lsTASK       PID     STATUS    busybox    5111    RUNNING[root@containerd ~]# # pid=5111[root@containerd ~]# pid=$(ctr -n k8s.io t ls|grep busybox|awk '{print $2}')[root@containerd ~]# netnspath=/proc/$pid/ns/net[root@containerd ~]# CNI_PATH=/root/cni-plugins /root/cni/scripts/exec-plugins.sh add $pid $netnspath

随后进入busybox容器我们将会发现其新增了一张网卡并可以实现外部网络访问：

[root@containerd ~]# ctr -n k8s.io task exec --exec-id $RANDOM -t busybox  sh -/ # ip a1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue qlen 1000    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00    inet 127.0.0.1/8 scope host lo       valid_lft forever preferred_lft forever    inet6 ::1/128 scope host        valid_lft forever preferred_lft forever3: eth0@if12: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1500 qdisc noqueue     link/ether d2:f2:8d:53:fc:95 brd ff:ff:ff:ff:ff:ff    inet 10.22.0.13/24 brd 10.22.0.255 scope global eth0       valid_lft forever preferred_lft forever    inet6 fe80::d0f2:8dff:fe53:fc95/64 scope link        valid_lft forever preferred_lft forever/ # ping 114.114.114.114PING 114.114.114.114 (114.114.114.114): 56 data bytes64 bytes from 114.114.114.114: seq=0 ttl=127 time=17.264 ms64 bytes from 114.114.114.114: seq=0 ttl=127 time=13.838 ms64 bytes from 114.114.114.114: seq=1 ttl=127 time=18.024 ms64 bytes from 114.114.114.114: seq=2 ttl=127 time=15.316 ms

小试牛刀：按照上述方法分别创建两个名为busybox-1与busybox-2容器，借助nc -l -p 8080暴露TCP服务端口进行彼此通信。

五、与宿主机共享目录

通过执行如下方案，我们即可实现容器与宿主机的/tmp进行共享：

[root@docker scripts]# ctr -n k8s.io c create v4ehxdz8.mirror.aliyuncs.com/library/busybox:latest busybox1 --mount type=bind,src=/tmp,dst=/host,options=rbind:rw[root@docker scripts]# ctr -n k8s.io t start -d busybox1 bash[root@docker scripts]# ctr -n k8s.io t exec -t --exec-id $RANDOM busybox1 sh/ # echo "Hello world" > /host/1 / # [root@docker scripts]# cat /tmp/1 Hello world

六、与其它容器共享ns

本节仅对pid ns共享进行举例，其它ns共享与该方案类似

首先我们对docker的ns共享进行实验：

[root@docker scripts]# docker run --rm -it -d busybox sh687c80243ee15e0a2171027260e249400feeeee2607f88d1f029cc270402cdd1[root@docker scripts]# docker run --rm -it -d --pid="container:687c80243ee15e0a2171027260e249400feeeee2607f88d1f029cc270402cdd1" busybox catfa2c09bd9c042128ebb2256685ce20e265f4c06da6d9406bc357d149af7b83d2[root@docker scripts]# docker ps -aCONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMESfa2c09bd9c04        busybox             "cat"               2 seconds ago       Up 1 second                             pedantic_goodall687c80243ee1        busybox             "sh"                22 seconds ago      Up 21 seconds                           hopeful_franklin[root@docker scripts]# docker exec -it 687c80243ee1 sh/ # ps auxPID   USER     TIME  COMMAND    1 root      0:00 sh    8 root      0:00 cat   15 root      0:00 sh   22 root      0:00 ps aux

接下来仿照该方案我们基于containerd的方式实现pid ns共享：

[root@docker scripts]# ctr -n k8s.io t lsTASK        PID     STATUS    busybox     2255    RUNNINGbusybox1    2652    RUNNING[root@docker scripts]# # 这里的2652即为已有task运行时的pid号[root@docker scripts]# ctr -n k8s.io c create --with-ns "pid:/proc/2652/ns/pid" v4ehxdz8.mirror.aliyuncs.com/library/python:3.6-slim python[root@docker scripts]# ctr -n k8s.io t start -d python python  # 这里启动了一个python的命令[root@docker scripts]# ctr -n k8s.io t exec -t --exec-id $RANDOM busybox1 sh/ # ps auxPID   USER     TIME  COMMAND    1 root      0:00 sh   34 root      0:00 python3   41 root      0:00 sh   47 root      0:00 ps aux

七、docker/containerd并用

参考链接：https://docs.docker.com/engine/reference/commandline/dockerd/
在完成对containerd的安装/配置启动后，我们可以在宿主机中安装docker客户端及服务。执行如下指令：

yum install -y yum-utils device-mapper-persistent-data lvm2yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repoyum update -y && yum install -y docker-ce-18.06.2.cesystemctl enable docker

编辑/etc/systemd/system/multi-user.target.wants/docker.service文件并为其新增--containerd启动项：

保存，推出后执行如下指令：

[root@docker ~]# systemctl daemon-reload[root@docker ~]# systemctl start docker[root@docker ~]# ps aux|grep dockerroot      72570  5.0  2.9 872668 55216 ?        Ssl  01:31   0:00 /usr/bin/dockerd --containerd /run/containerd/containerd.sock --debug

进行验证：

END

码农公寓

一、安装Containerd

二、运行一个busybox镜像：

三、创建CNI网络

四、使containerd容器具备网络功能

五、与宿主机共享目录

六、与其它容器共享ns

七、docker/containerd并用

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