轻量级Kubernetes之k3s：16:源码编译k3s

这篇文章介绍一下源码编译k3s的方法。

事前准备 go语言环境

go语言版本需要go 1.12，本文示例使用1.13.5[root@liumiaocn ~]# go version go version go1.13.5 linux/amd64 [root@liumiaocn ~]# ，安装步骤如下所示

步骤1: 下载go语言安装包

执行命令：wget https://dl.google.com/go/go1.13.5.linux-amd64.tar.gz

步骤2: 设定环境变量

在/etc/profile中设定GOROOT和PATH，详细如下所示

[root@liumiaocn ~]# tail -n2 /etc/profile
export GOROOT=/usr/local/go
export PATH=$PATH:${GOROOT}/bin
[root@liumiaocn ~]#

步骤3：确认版本

重新登录之后即可执行go version确认版本

[root@liumiaocn ~]# go version
go version go1.13.5 linux/amd64
[root@liumiaocn ~]#

安装gcc

安装命令：yum install gcc

安装libseccomp开发包

CentOS/RHEL下： yum install libseccomp-devel Ubuntu/Debian下： apt-get install libseccomp-dev

下载k3s源码包

[root@liumiaocn ~]# git clone http://github.com/rancher/k3s.git
Cloning into 'k3s'...
remote: Enumerating objects: 37, done.
remote: Counting objects: 100% (37/37), done.
remote: Compressing objects: 100% (29/29), done.
remote: Total 926826 (delta 10), reused 18 (delta 5), pack-reused 926789
Receiving objects: 100% (926826/926826), 518.39 MiB | 22.51 MiB/s, done.
Resolving deltas: 100% (676821/676821), done.
Checking out files: 100% (12503/12503), done.
[root@liumiaocn ~]#

或者使用如下命令下载源码1.0.0的源码压缩包

wget https://github.com/rancher/k3s/archive/v1.0.0.tar.gz

编译k3s

[root@liumiaocn ~]# cd k3s
[root@liumiaocn k3s]# ls 
BUILDING.md                 LICENSE    Vagrantfile  docker-compose.yml  go.sum       main.go    pkg      vendor
Dockerfile.dapper           Makefile   cmd          e2e                 install.sh   manifests  scripts  vendor.go
Dockerfile.sonobuoy.dapper  README.md  contrib      go.mod              k3s.service  package    tests
[root@liumiaocn k3s]# go build -o k3s
go: downloading github.com/sirupsen/logrus v1.4.2
go: downloading github.com/rancher/kubernetes/staging/src/k8s.io/client-go v1.16.3-k3s.2
go: downloading github.com/pkg/errors v0.8.1
go: downloading github.com/rancher/kubernetes/staging/src/k8s.io/apimachinery v1.16.3-k3s.2
go: downloading github.com/rootless-containers/rootlesskit v0.6.0
...省略
[root@liumiaocn k3s]# ls
bin          cmd                 Dockerfile.dapper           etc     install.sh   LICENSE   manifests  README.md  Vagrantfile
build        contrib             Dockerfile.sonobuoy.dapper  go.mod  k3s          main.go   package    scripts    vendor
BUILDING.md  docker-compose.yml  e2e                         go.sum  k3s.service  Makefile  pkg        tests      vendor.go
[root@liumiaocn k3s]# ./k3s --version
k3s version dev (HEAD)
[root@liumiaocn k3s]#

注：如果希望构建完整版本的二进制文件，直接执行make即可。

常见错误

• 缺少libseccomp开发库

Package libseccomp was not found in the pkg-config search path.
Perhaps you should add the directory containing `libseccomp.pc'
to the PKG_CONFIG_PATH environment variable
No package 'libseccomp' found

CentOS/RHEL下： yum install libseccomp-devel Ubuntu/Debian下： apt-get install libseccomp-dev

• make构建完整版本二进制文件时需要docker启动状态

[root@liumiaocn k3s]# make
./.dapper ci
Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?
FATA[0005] exit status 1                                
make: *** [ci] Error 1
[root@liumiaocn k3s]# systemctl start docker
[root@liumiaocn k3s]#

• 内存不够 很多显示为signal killed的错误可能都是因为可用内存过少导致的，可考虑增大可用内存再试

/usr/local/go/pkg/tool/linux_amd64/link: signal: killed

内存实在不足时，也可以考虑增加swap来应对，只是速度会慢一些，比如使用如下的方式增加1G的swap

[root@liumiaocn ~]# swapon
NAME  TYPE SIZE USED PRIO
/swap file 132M   0B   -1
[root@liumiaocn ~]# 
[root@liumiaocn ~]# dd if=/dev/zero of=/root/swapfile bs=1M count=1024
1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB) copied, 2.52969 s, 424 MB/s
[root@liumiaocn ~]# 
[root@liumiaocn ~]# mkswap /root/swapfile
Setting up swapspace version 1, size = 1048572 KiB
no label, UUID=feb9aea6-2e80-4473-ae58-56c18d49699b
[root@liumiaocn ~]# 
[root@liumiaocn ~]# swapon /root/swapfile
swapon: /root/swapfile: insecure permissions 0644, 0600 suggested.
[root@liumiaocn ~]# 
[root@liumiaocn ~]# vi /etc/fstab
[root@liumiaocn ~]# 
[root@liumiaocn ~]# grep swapfile /etc/fstab
/root/swapfile swap swap defaults 0 0
[root@liumiaocn ~]# 
[root@liumiaocn ~]# swapon
NAME           TYPE  SIZE USED PRIO
/swap          file  132M   0B   -1
/root/swapfile file 1024M   0B   -2
[root@liumiaocn ~]#

参考内容

https://docs.rancher.cn/k3s/building.html#_1-kubernetes-source