DEVOPS技术实践_15：使用Docker作为Jenkins的slave

前面实验了使用docker搭建一个jenkins，下面实验使用docker作为jenkins的slave节点

1. 环境准备

• 一个运行Docker的主机或者群集
• Jenkins应该能访问互联网，方便安装插件。
• Jenkins服务器能够和GitHub通信。
• Jenkinss对Java所需要的Git,和Maven配置应该配置好。
• 一个Jenkins master.

2. 在Docker主机上开启远端的访问API

此处针对Docker 18.03

/etc/docker/daemon.json会被docker.service的配置文件覆盖，直接添加daemon.json不起作用。可以有如下几种设置：

直接编辑配置文件：Centos中docker daemon配置文件在/lib/systemd/system/docker.service，找到以下字段，在后面添加如下，注意，此处不能用”fd：//”,否则报错

[Unit]
Description=Docker Application Container Engine
Documentation=https://docs.docker.com
BindsTo=containerd.service
After=network-online.target firewalld.service containerd.service
Wants=network-online.target
Requires=docker.socket

[Service]
Type=notify
# the default is not to use systemd for cgroups because the delegate issues still
# exists and systemd currently does not support the cgroup feature set required
# for containers run by docker
#ExecStart=/usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock
ExecStart=/usr/bin/dockerd -H unix:///var/run/docker.sock -H tcp://0.0.0.0:2375    #添加
ExecReload=/bin/kill -s HUP $MAINPID
TimeoutSec=
RestartSec=
Restart=always

# Note that StartLimit* options were moved from "Service" to "Unit" in systemd .
# Both the old, and new location are accepted by systemd  and up, so using the old location
# to make them work for either version of systemd.
StartLimitBurst=

# Note that StartLimitInterval was renamed to StartLimitIntervalSec in systemd .
# Both the old, and new name are accepted by systemd  and up, so using the old name to make
# this option work for either version of systemd.
StartLimitInterval=60s

# Having non-zero Limit*s causes performance problems due to accounting overhead
# in the kernel. We recommend using cgroups to do container-local accounting.
LimitNOFILE=infinity
LimitNPROC=infinity
LimitCORE=infinity

# Comment TasksMax if your systemd version does not support it.
# Only systemd  and above support this option.
TasksMax=infinity

# set delegate yes so that systemd does not reset the cgroups of docker containers
Delegate=yes

执行

[root@node6 ~]# systemctl daemon-reload

[root@node6 ~]# systemctl restart docker.service

安装Docker插件

点击【管理Jenkins】–【管理插件】–【可选插件】然后安装此插件

3. 配置Docker插件

点击系统管理----->系统设置

添加配置

然后点击保存

4. 创建Docker镜像

需要创建一个Docker的镜像在Docker主机上，方便我们在创建Jenkins slaves时使用。

查看Docker的镜像

[root@node6 ~]# docker images

REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
jenkins/jenkins     lts                 fac78e370c0b         days ago          568MB

拉取ubuntu的镜像

由于拉取的Ubuntu安装git有点问题，重新拉去一个ubuntu16.04的镜像

[root@node6 ~]# docker pull dftbcros.mirror.aliyuncs.com/library/ubuntu:16.04

16.04: Pulling from library/ubuntu
e80174c8b43b: Pull complete
d1072db285cc: Pull complete
858453671e67: Pull complete
3d07b1124f98: Pull complete
Digest: sha256:bb5b48c7750a6a8775c74bcb601f7e5399135d0a06de004d000e05fd25c1a71c
Status: Downloaded newer image for dftbcros.mirror.aliyuncs.com/library/ubuntu:16.04
dftbcros.mirror.aliyuncs.com/library/ubuntu:16.04 

[root@node6 ~]# docker images

REPOSITORY                                    TAG                 IMAGE ID            CREATED             SIZE
dftbcros.mirror.aliyuncs.com/library/ubuntu   16.04               5f2bf26e3524         days ago          123MB
jenkins/jenkins                               lts                 fac78e370c0b         days ago          568MB
centos                                        latest              0f3e07c0138f         weeks ago         220MB

[root@node6 ~]# docker pull centos

Using default tag: latest
latest: Pulling from library/centos
729ec3a6ada3: Pull complete
Digest: sha256:f94c1d992c193b3dc09e297ffd54d8a4f1dc946c37cbeceb26d35ce1647f88d9
Status: Downloaded newer image for centos:latest
docker.io/library/centos:latest

执行下面的命令运行Docker容器并在容器中执行命令。

root@37e4f2be0a41:/# apt-get update

Get: http://archive.ubuntu.com/ubuntu xenial InRelease [247 kB]
Get: http://security.ubuntu.com/ubuntu xenial-security InRelease [109 kB]
Get: http://security.ubuntu.com/ubuntu xenial-security/main amd64 Packages [985 kB]
Get: http://archive.ubuntu.com/ubuntu xenial-updates InRelease [109 kB]
Get: http://archive.ubuntu.com/ubuntu xenial-backports InRelease [107 kB]
Get: http://archive.ubuntu.com/ubuntu xenial/main amd64 Packages [1558 kB]
Get: http://security.ubuntu.com/ubuntu xenial-security/restricted amd64 Packages [12.7 kB]
Get: http://security.ubuntu.com/ubuntu xenial-security/universe amd64 Packages [589 kB]
Get: http://security.ubuntu.com/ubuntu xenial-security/multiverse amd64 Packages [6281 B]
Get: http://archive.ubuntu.com/ubuntu xenial/restricted amd64 Packages [14.1 kB]
Get: http://archive.ubuntu.com/ubuntu xenial/universe amd64 Packages [9827 kB]
Get: http://archive.ubuntu.com/ubuntu xenial/multiverse amd64 Packages [176 kB]
Get: http://archive.ubuntu.com/ubuntu xenial-updates/main amd64 Packages [1362 kB]
Get: http://archive.ubuntu.com/ubuntu xenial-updates/restricted amd64 Packages [13.1 kB]
Get: http://archive.ubuntu.com/ubuntu xenial-updates/universe amd64 Packages [993 kB]
Get: http://archive.ubuntu.com/ubuntu xenial-updates/multiverse amd64 Packages [19.3 kB]
Get: http://archive.ubuntu.com/ubuntu xenial-backports/main amd64 Packages [7942 B]
Get: http://archive.ubuntu.com/ubuntu xenial-backports/universe amd64 Packages [8807 B]
Fetched 16.1 MB in 6min 48s (39.5 kB/s)
Reading package lists... Done

安装git

root@37e4f2be0a41:/# apt-get install -y git

添加用户

root@:37e4f2be0a41/# adduser  jenkins
Adding user `jenkins' ...
Adding new group `jenkins' (1000) ...
Adding new user `jenkins' (1000) with group `jenkins' ...
Creating home directory `/home/jenkins' ...
Copying files from `/etc/skel' ...
Enter new UNIX password:
Retype new UNIX password:
passwd: password updated successfully
Changing the user information for jenkins
Enter the new value, or press ENTER for the default
    Full Name []:
    Room Number []:
    Work Phone []:
    Home Phone []:
    Other []:
Is the information correct? [Y/n] Y

安装SSH server

root@37e4f2be0a41:/# apt-get install openssh-serverd

root@37e4f2be0a41:/# mkdir /var/run/sshd

5. 安装所需的应用

root@37e4f2be0a41:/# apt-get install openjdk-8-jdk -y

root@37e4f2be0a41:/# apt-get install maven

root@37e4f2be0a41:/# exit

[root@node6 ~]# docker ps -a

37e4f2be0a41        5f2bf26e3524          "/bin/bash"              About an hour ago   Exited ()  seconds ago                           sweet_hypatia

6. 保存镜像

[root@node6 ~]#  docker commit b119e7f28b50  maven-build-slave-0.2

sha256:3a444723b0557cf81661b3f95947c3deae8c93008476ac3a86cbb8b7979815ce

[root@node6 ~]# docker images

maven-build-slave-0.2                         latest              3a444723b055        About a minute ago   568MB

7. jenkins配置docker凭据

系统管理----->系统设置

创建凭据

配置模板

保存

8. jenkins测试

使用这个项目

pipeline语法

node('docker') {
    // some block
    stage('Preparation') {
    // some block
    //step
    git 'https://github.com/jglick/simple-maven-project-with-tests.git'
}
    stage('Build') {
    // some block
    //step
    withMaven(maven: 'M3') {
    // some block
    sh label: '', script: 'mvn -Dmaven.test.failuer.ignore clean install package'
}
}
}

构建即可