基于Centos7安装k8s集群(k8s+crio+podman)
一、前言dockershimCRIcri-ocontainerd二、CRI-O, Containerd, Docker daemon 对比cri三者区别如图:三、k8s+crio+podman实现3.1 podman安装三台机都需要安装podman3.2 k8s的安装参考:三台机都需要安装kubeletkubeadmkubectl,并启动kubelet3.2 cri-o的安装3.2.1 Ubunt
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一、前言
在传统的 k8s集群中,使用docker engine做为底层的容器管理软件的,而docker engine因为不是k8s亲生的解决方案,所以实际使用中会有更多的分层。k8s为了调用docker engine,专门写了一个 dockershim做为 CRI,而在1.20版本的时候,k8s就宣布停止更新dockershim了,也就是说再往后的版本就不推荐使用 k8s+dockershim+docker engine的方案了。
而k8s官方比较推荐的解决方案中,官方比较推荐的是 cri-o或者 containerd,前者是基于开放容器计划(OCI)的实现,后者是基于docker的containerd,后脱离出来进行独立开发的组件,现归属于 CNCF组织。
二、CRI-O, Containerd, Docker daemon 对比
三者区别:
1. cri-o是 cri的实现,可以直接调用底层的runc
2. containerd是 CRI-Containerd的实现,可以调用底层的runc
3. docker需要先调用dockershim,然后调用docker,再调用containerd,最后调用底层的runc:
docker --> dockershim --> docker --> containerd --> runc
三者区别如图:
三、k8s+crio+podman实现
3.1 podman安装
参考:docker的平替–podman - eryoung2 - 博客园
三台机都需要安装podman
3.2 k8s的安装
参考: kubernetes 搭建集群 - eryoung2 - 博客园
三台机都需要安装kubelet/kubeadm/kubectl,并启动kubelet
3.2 cri-o的安装
3.2.1 Ubuntu(18.04)安装cri-o
3.2.1.1 准备
$. modprobe overlay # 打开overlay
$. modprobe br_netfilter # 打开netfilter
$. cat > /etc/sysctl.d/99-kubernetes-cri.conf <<EOF #内核处理
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip\_forward = 1
net.bridge.bridge-nf-call-ip6tables = 1
EOF
$. sysctl --system
$. swapoff -a #kube scheduler要求关闭swap
3.2.1.2 安装CRI-O
# 指定版本
$. OS=xUbuntu_18.04
$. CRIO\_VERSION=1.23
# 加源
$. echo "deb https://download.opensuse.org/repositories/devel:/kubic:/libcontainers:/stable/$OS/ /"|sudo tee /etc/apt/sources.list.d/devel:kubic:libcontainers:stable.list
$. echo "deb http://download.opensuse.org/repositories/devel:/kubic:/libcontainers:/stable:/cri-o:/$CRIO\_VERSION/$OS/ /"|sudo tee /etc/apt/sources.list.d/devel:kubic:libcontainers:stable:cri-o:$CRIO\_VERSION.list
# 加key
$. curl -L https://download.opensuse.org/repositories/devel:kubic:libcontainers:stable:cri-o:$CRIO\_VERSION/$OS/Release.key | sudo apt-key add -
$. curl -L https://download.opensuse.org/repositories/devel:/kubic:/libcontainers:/stable/$OS/Release.key | sudo apt-key add -
# 安装
$. sudo apt update -y
$. sudo apt install cri-o cri-o-runc cri-tools -y
3.2.1.3 检查CRI-O
$. apt show cri-o
Package: cri-o
Version: 1.23.3~0
Priority: optional
Section: devel
Maintainer: Peter Hunt <haircommander@fedoraproject.org>
Installed-Size: 98.3 MB
Depends: libgpgme11, libseccomp2, conmon, containers-common (>= 0.1.27) | golang-github-containers-common, tzdata
Suggests: cri-o-runc | runc (>= 1.0.0), containernetworking-plugins
Replaces: cri-o-1.19, cri-o-1.20, cri-o-1.21, cri-o-1.22
Homepage: https://github.com/cri-o/cri-o
Download-Size: 19.9 MB
APT-Manual-Installed: yes
APT-Sources: http://download.opensuse.org/repositories/devel:/kubic:/libcontainers:/stable:/cri-o:/1.23/xUbuntu_18.04 Packages
Description: OCI-based implementation of Kubernetes Container Runtime Interface.
N: Ignoring file 'ystemctlqq' in directory '/etc/apt/sources.list.d/' as it has no filename extension
$. systemctl enable crio.service
$. systemctl start crio.service
$. systemctl status crio
● crio.service - Container Runtime Interface for OCI (CRI-O)
Loaded: loaded (/usr/lib/systemd/system/crio.service; enabled; vendor preset: enabled)
Active: active (running) since Wed 2022-07-13 01:26:03 CST; 16h ago
Docs: https://github.com/cri-o/cri-o
Main PID: 5338 (crio)
Tasks: 15
CGroup: /system.slice/crio.service
└─5338 /usr/bin/crio
3.2.1.4 使用cri-o
查看状态
root@home:~# crictl info
{
"status": {
"conditions": [
{
"type": "RuntimeReady",
"status": true,
"reason": "",
"message": ""
},
{
"type": "NetworkReady",
"status": true,
"reason": "",
"message": ""
}
]
}
}
查看镜像
root@home:~# crictl images
IMAGE TAG IMAGE ID SIZE
docker.io/calico/cni v3.23.2 a87d3f6f1b8fd 263MB
docker.io/calico/node v3.23.2 a3447b26d32c7 224MB
docker.io/library/nginx latest 41b0e86104ba6 146MB
k8s.gcr.io/coredns/coredns v1.8.6 a4ca41631cc7a 47MB
k8s.gcr.io/etcd 3.5.3-0 aebe758cef4cd 301MB
k8s.gcr.io/kube-apiserver v1.24.2 d3377ffb7177c 131MB
k8s.gcr.io/kube-controller-manager v1.24.2 34cdf99b1bb3b 121MB
k8s.gcr.io/kube-proxy v1.24.2 a634548d10b03 112MB
k8s.gcr.io/kube-scheduler v1.24.2 5d725196c1f47 52.3MB
k8s.gcr.io/pause 3.6 6270bb605e12e 690kB
k8s.gcr.io/pause 3.7 221177c6082a8 718kB
3.2.2 Centos(7)安装cri-o
3.2.2.1 准备
$. VERSION=1.22
$. sudo curl -L -o /etc/yum.repos.d/devel:kubic:libcontainers:stable.repo https://download.opensuse.org/repositories/devel:kubic:libcontainers:stable/CentOS_7/devel:kubic:libcontainers:stable.repo
$. sudo curl -L -o /etc/yum.repos.d/devel:kubic:libcontainers:stable:cri-o:${VERSION}.repo https://download.opensuse.org/repositories/devel:kubic:libcontainers:stable:cri-o:${VERSION}/CentOS_7/devel:kubic:libcontainers:stable:cri-o:${VERSION}.repo
3.2.2.2 安装
$. yum update -y
$. yum install cri-o cri-tools -y
3.2.2.3 查看cri-o版本
[root@node1 systemd]# rpm -qi cri-o
Name : cri-o
Epoch : 0
Version : 1.22.5
Release : 2.2.el7
Architecture: x86_64
Install Date: 2022年07月13日 星期三 01时36分47秒
Group : Unspecified
Size : 236845729
License : ASL 2.0
Signature : RSA/SHA256, 2022年07月10日 星期日 12时53分28秒, Key ID 4d64390375060aa4
Source RPM : cri-o-1.22.5-2.2.el7.src.rpm
Build Date : 2022年07月10日 星期日 12时53分00秒
Build Host : sheep87
Relocations : (not relocatable)
Vendor : obs://build.opensuse.org/devel:kubic
URL : https://github.com/cri-o/cri-o
Summary : Open Container Initiative-based implementation of Kubernetes Container Runtime Interface
Description :
Open Container Initiative-based implementation of Kubernetes Container Runtime
Interface.
3.2.2.4 启动cri-o
$. systemctl enable crio --now
3.2.2.5 查看cri-o状态
[root@node1 systemd]# systemctl status crio
● crio.service - Container Runtime Interface for OCI (CRI-O)
Loaded: loaded (/usr/lib/systemd/system/crio.service; enabled; vendor preset: disabled)
Active: active (running) since 三 2022-07-13 01:41:06 CST; 16h ago
Docs: https://github.com/cri-o/cri-o
Main PID: 24127 (crio)
Tasks: 15
Memory: 13.7M
CGroup: /system.slice/crio.service
└─24127 /usr/bin/crio
三台机都安装cri-o并启动。
四、K8S启动
4.1 创建k8s集群
在master上,执行下列命令:
$. kubeadm init \
--apiserver-advertise-address 192.168.1.150 \
--apiserver-bind-port 6443 \
--kubernetes-version 1.24.2 \
--pod-network-cidr 10.244.0.0/16
--apiserver-advertise-address 集群master地址
--image-repository 由于默认拉取镜像地址k8s.gcr.io国内无法访问,这里指定阿里云镜像仓库地址
--kubernetes-version K8s版本,与上面安装的一致
--service-cidr 集群内部虚拟网络,Pod统一访问入口
--pod-network-cidr Pod网络,与下面部署的CNI网络组件yaml中保持一致
初始化之后,会输出一个join命令,先复制出来,node节点加入master会使用。
然后等5分钟,k8s集群的master node完成创建。
Your Kubernetes control-plane has initialized successfully!
To start using your cluster, you need to run the following as a regular user:
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
Alternatively, if you are the root user, you can run:
export KUBECONFIG=/etc/kubernetes/admin.conf
You should now deploy a pod network to the cluster.
Run "kubectl apply -f [podnetwork].yaml" with one of the options listed at:
https://kubernetes.io/docs/concepts/cluster-administration/addons/
Then you can join any number of worker nodes by running the following on each as root:
kubeadm join 192.168.1.150:6443 --token gjxt6y.0wljlhfkjz90v12m --discovery-token-ca-cert-hash sha256:d69fc5929e442210c97ab85c05a8c2906f5819a74d5b0fa3481032d6a8f3fc07
1234567891011121314151617181920
在所有node机器节点运行命令:
$. mkdir -p $HOME/.kube
$. sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
$. sudo chown $(id -u):$(id -g) $HOME/.kube/config
# 否则会报错
The connection to the server localhost:8080 was refused - did you specify the right host or port?
4.2 检查集群
在以上所有内容都完成之后,查看nodes或者pods:
root@home:~# kubectl get nodes
NAME STATUS ROLES AGE VERSION
home Ready control-plane 179m v1.24.2
node1 Ready <none> 179m v1.24.2
node2 Ready <none> 179m v1.24.2
root@home:~# kubectl get pods -A
NAMESPACE NAME READY STATUS RESTARTS AGE
kube-system coredns-6d4b75cb6d-4wxjh 1/1 Running 0 179m
kube-system coredns-6d4b75cb6d-7qxpv 1/1 Running 0 179m
kube-system etcd-home 1/1 Running 2 3h
kube-system kube-apiserver-home 1/1 Running 2 3h
kube-system kube-controller-manager-home 1/1 Running 2 3h
kube-system kube-proxy-9w7mf 1/1 Running 0 179m
kube-system kube-proxy-hpw6c 1/1 Running 0 179m
kube-system kube-proxy-tbpr8 1/1 Running 0 179m
kube-system kube-scheduler-home 1/1 Running 2 3h
鸣谢
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