使用 Kubeadm 快速部署 Kubernetes

Posted by Mike on 2017-03-23

Kubernetes是什么?

Kubernetes是Google开源的基于Docker的容器集群管理系统,是谷歌内部大规模集群管理系统Borg的开源版本。Kubernetes基于Borg集群软件模型,其诱人之处在于该模型经过了Google庞大数据中心的校验。

Kubernetes(K8s)是一个真正的平台,提供运行环境,使得复杂要求的应用在上面构建。它通过yaml语言写的配置文件,很简单快速的就能自动通过Docker镜像部署好应用环境,支持应用横向扩展,并且可以组织、编排、管理和迁移这些容器化的应用。

本文主要介绍在Ubuntu 16.04上使用kubeadm搭建一个集群环境。

Kubernetes架构

Kubernetes地位

K8s的地位如上图所示,优点是有很好的可移植性和可扩展性。关于K8s,这两个重要的性质表现在:

  • 可移植性:K8s可以搭建在阿里云、Amazon、Microsoft Azure、Google Cloud上,也可以搭建在任何的公有云和私有云上。
  • 可扩展性:K8s在GitHub上托管,截至2017年3月1日有来自全球的1100名贡献者,为它提供了Dashboard、网络构件等扩展工具。

Kubernetes的核心组件

Kubernetes将集群中的机器分为一个Master节点和一组Node节点。从kubernetes 1.4开始,各个核心组件也是以容器形式运行在Master的node上。

其中Master节点上运行kube-apiserver,kube-controller-manager,kube-scheduler,这些容器负责整个集群的资源管理、Pod调度、安全控制、弹性伸缩和系统监控。Node节点是集群中的工作节点,运行真正的服务。

Pod是Node节点上的基本单元。Node节点上运行着kubelet进程,还有kube-proxy容器,它们负责Pod的创建、启动、监控、重启、销毁,同时实现负载均衡器。真正需要运行的服务被包装到对应的Pod中,成为Pod中运行的一个容器。

Kubernetes官网: https://kubernetes.io/
Kubernetes中文社区: https://www.kubernetes.org.cn/

前期环境准备与约束

准备了两台Ubuntu 16.04虚拟机,各项参数如下:

节点机器名 IP地址 CPU 内存
dev-master-01 10.211.55.11 2核 2GB
dev-node-01 10.211.55.12 2核 1GB

Kubernetes官网上提到每台机器至少要有1GB内存,不然集群运行之后,留给运行在容器内的应用的内存就很少了。同时要保证所有机器之前的网络是互相连通的。

部署Kubernetes Master

安装内容包括:

  • docker:容器运行的软件。
  • kubelet:kubelet是Kubernets最重要的组件,它要运行在集群上所有的机器,用来执行类似于开启pods和容器。
  • kubectl:在集群运行时,控制容器的部件。只需要将其运行在主节点上,但是它将对所有节点都有效。
  • Kubeadm:集群的引导程序。

安装Kubernetes相关软件包

由于墙的原因无法直接访问到Google的软件仓库(packages.cloud.google.com)和容器仓库(gcr.io),解决方法有两种:一是直接配置的Hosts文件,二是使用三方源或转存的容器仓库。这里使用修改Hosts文件的方法。

把下面几行内容加入到hosts文件中

1
2
3
4
5
$ vim  /etc/hosts

61.91.161.217 gcr.io
61.91.161.217 www.gcr.io
61.91.161.217 packages.cloud.google.com

最新可用的Google hosts文件可在这里获取:https://github.com/racaljk/hosts

  • 安装kubernetes相关软件包
1
2
3
4
5
6
$ curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | apt-key add -
$ cat <<EOF > /etc/apt/sources.list.d/kubernetes.list
deb http://apt.kubernetes.io/ kubernetes-xenial main
EOF
$ apt-get update
$ apt-get install -y kubelet kubeadm kubectl kubernetes-cni
  • 安装Docker

直接通过安装脚本一键安装Docker

1
$ curl -sSL http://acs-public-mirror.oss-cn-hangzhou.aliyuncs.com/docker-engine/internet | sh -
  • 清除可能与kubernetes冲突的设置

关闭 SELinux

1
2
$ apt install -y selinux-utils
$ setenforce 0

清除iptables

避免自定义iptables影响kubernetes服务工作,建议自定义需求通过kubernetes实现。如果满足不了,安装好kubernetes后,再配置自定义iptables。

1
2
3
$ iptables -t filter -F
$ iptables -t nat -F
$ iptables -t mangle -F
  • 准备镜像

下载docker镜像

由于墙的原因,从Google下载相关镜像速度很慢。为了更加顺利的搭建集群,建议优先下载好相应镜像。

Kubernetes-1.5.2所需要的镜像:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
$ docker pull gcr.io/google_containers/kube-apiserver-amd64:v1.5.4
$ docker pull gcr.io/google_containers/kube-controller-manager-amd64:v1.5.4
$ docker pull gcr.io/google_containers/kube-scheduler-amd64:v1.5.4
$ docker pull gcr.io/google_containers/kube-proxy-amd64:v1.5.4
$ docker pull gcr.io/google_containers/kube-apiserver-amd64:v1.5.2
$ docker pull gcr.io/google_containers/kube-scheduler-amd64:v1.5.2
$ docker pull gcr.io/google_containers/kube-controller-manager-amd64:v1.5.2
$ docker pull gcr.io/google_containers/etcd-amd64:3.0.14-kubeadm
$ docker pull gcr.io/google_containers/kubedns-amd64:1.9
$ docker pull gcr.io/google_containers/dnsmasq-metrics-amd64:1.0
$ docker pull gcr.io/google_containers/kube-dnsmasq-amd64:1.4
$ docker pull gcr.io/google_containers/kube-discovery-amd64:1.0
$ docker pull gcr.io/google_containers/exechealthz-amd64:1.2
$ docker pull gcr.io/google_containers/pause-amd6:3.0
$ docker pull gcr.io/google_containers/kubernetes-dashboard-amd64:v1.6.0
$ docker pull quay.io/coreos/flannel:v0.7.0-amd64

部署Kubernetes master

理论上通过kubeadm使用init和join命令即可建立一个集群,这init就是在master节点对集群进行初始化。和k8s 1.4之前的部署方式不同的是kubeadm安装的k8s核心组件都是以容器的形式运行于master node上的。

初始化master

使用kubeadm init初始化kubernetes master。

1
$ kubeadm init --use-kubernetes-version=v1.5.2 --pod-network-cidr=10.244.0.0/16

说明:kubeadm init并没有为你选择一个默认的Pod network进行安装。这里使用flannel作为Pod network。那么在执行init时,我们必须给init命令带上--pod-network-cidr=10.244.0.0/16

如果有多网卡的,请根据实际情况配置--api-advertise-addresses=<ip-address>,单网卡情况可以省略。

1
$ kubeadm init --use-kubernetes-version=v1.5.2 --pod-network-cidr=10.244.0.0/16 --api-advertise-addresses=10.211.55.11

实测中发现kubeadm暂时还不支持docker 17.03.0-ce版本,会报以下错误:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
$ kubeadm init --pod-network-cidr=10.244.0.0/16
[kubeadm] WARNING: kubeadm is in alpha, please do not use it for production clusters.
[preflight] Running pre-flight checks
[preflight] The system verification failed. Printing the output from the verification:
OS: Linux
KERNEL_VERSION: 4.4.0-62-generic
CONFIG_NAMESPACES: enabled
CONFIG_NET_NS: enabled
CONFIG_PID_NS: enabled
CONFIG_IPC_NS: enabled
CONFIG_UTS_NS: enabled
CONFIG_CGROUPS: enabled
CONFIG_CGROUP_CPUACCT: enabled
CONFIG_CGROUP_DEVICE: enabled
CONFIG_CGROUP_FREEZER: enabled
CONFIG_CGROUP_SCHED: enabled
CONFIG_CPUSETS: enabled
CONFIG_MEMCG: enabled
CONFIG_INET: enabled
CONFIG_EXT4_FS: enabled
CONFIG_PROC_FS: enabled
CONFIG_NETFILTER_XT_TARGET_REDIRECT: enabled (as module)
CONFIG_NETFILTER_XT_MATCH_COMMENT: enabled (as module)
CONFIG_OVERLAY_FS: enabled (as module)
CONFIG_AUFS_FS: enabled (as module)
CONFIG_BLK_DEV_DM: enabled
CGROUPS_CPU: enabled
CGROUPS_CPUACCT: enabled
CGROUPS_CPUSET: enabled
CGROUPS_DEVICES: enabled
CGROUPS_FREEZER: enabled
CGROUPS_MEMORY: enabled
DOCKER_VERSION: 17.03.0-ce
[preflight] Some fatal errors occurred:
unsupported docker version: 17.03.0-ce
[preflight] If you know what you are doing, you can skip pre-flight checks with `--skip-preflight-checks`

根据提示加上--skip-preflight-checks参数后,继续初始化master。

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
$ kubeadm init --pod-network-cidr=10.244.0.0/16 --skip-preflight-checks
[kubeadm] WARNING: kubeadm is in alpha, please do not use it for production clusters.
[preflight] Skipping pre-flight checks
[preflight] Starting the kubelet service
[init] Using Kubernetes version: v1.5.4
[tokens] Generated token: "e4f68e.6cc8c11c93148cd7"
[certificates] Generated Certificate Authority key and certificate.
[certificates] Generated API Server key and certificate
[certificates] Generated Service Account signing keys
[certificates] Created keys and certificates in "/etc/kubernetes/pki"
[kubeconfig] Wrote KubeConfig file to disk: "/etc/kubernetes/admin.conf"
[kubeconfig] Wrote KubeConfig file to disk: "/etc/kubernetes/kubelet.conf"
[apiclient] Created API client, waiting for the control plane to become ready
[apiclient] All control plane components are healthy after 62.298779 seconds
[apiclient] Waiting for at least one node to register and become ready
[apiclient] First node is ready after 0.508216 seconds
[apiclient] Creating a test deployment
[apiclient] Test deployment succeeded
[token-discovery] Created the kube-discovery deployment, waiting for it to become ready
[token-discovery] kube-discovery is ready after 23.003368 seconds
[addons] Created essential addon: kube-proxy
[addons] Created essential addon: kube-dns

Your Kubernetes master has initialized successfully!

You should now deploy a pod network to the cluster.
Run "kubectl apply -f [podnetwork].yaml" with one of the options listed at:
http://kubernetes.io/docs/admin/addons/

You can now join any number of machines by running the following on each node:

kubeadm join --token=e4f68e.6cc8c11c93148cd7 10.211.55.11

初始化成功后,检查Kubernetes的核心组件均正常启动。

1
2
3
4
5
6
7
8
$ ps axu|grep kube
root 2641 10.6 3.8 442928 79672 ? Ssl 11:39 11:25 /usr/bin/kubelet --kubeconfig=/etc/kubernetes/kubelet.conf --require-kubeconfig=true --pod-manifest-path=/etc/kubernetes/manifests --allow-privileged=true --network-plugin=cni --cni-conf-dir=/etc/cni/net.d --cni-bin-dir=/opt/cni/bin --cluster-dns=10.96.0.10 --cluster-domain=cluster.local
root 2917 0.1 1.3 41268 28316 ? Ssl 11:40 0:09 kube-scheduler --address=127.0.0.1 --leader-elect --master=127.0.0.1:8080
root 2961 1.2 7.4 187696 151428 ? Ssl 11:40 1:18 kube-apiserver --insecure-bind-address=127.0.0.1 --admission-control=NamespaceLifecycle,LimitRanger,ServiceAccount,PersistentVolumeLabel,DefaultStorageClass,ResourceQuota --service-cluster-ip-range=10.96.0.0/12 --service-account-key-file=/etc/kubernetes/pki/apiserver-key.pem --client-ca-file=/etc/kubernetes/pki/ca.pem --tls-cert-file=/etc/kubernetes/pki/apiserver.pem --tls-private-key-file=/etc/kubernetes/pki/apiserver-key.pem --token-auth-file=/etc/kubernetes/pki/tokens.csv --secure-port=6443 --allow-privileged --advertise-address=10.211.55.11 --kubelet-preferred-address-types=InternalIP,ExternalIP,Hostname --anonymous-auth=false --etcd-servers=http://127.0.0.1:2379
root 3810 1.5 3.0 87448 62936 ? Ssl 11:56 1:22 kube-controller-manager --address=127.0.0.1 --leader-elect --master=127.0.0.1:8080 --cluster-name=kubernetes --root-ca-file=/etc/kubernetes/pki/ca.pem --service-account-private-key-file=/etc/kubernetes/pki/apiserver-key.pem --cluster-signing-cert-file=/etc/kubernetes/pki/ca.pem --cluster-signing-key-file=/etc/kubernetes/pki/ca-key.pem --insecure-experimental-approve-all-kubelet-csrs-for-group=system:kubelet-bootstrap --allocate-node-cidrs=true --cluster-cidr=10.244.0.0/16
root 4018 0.0 0.2 8136 5412 ? Ssl 11:56 0:00 /usr/local/bin/kube-discovery
root 5397 0.1 1.3 37788 28504 ? Ssl 11:56 0:06 kube-proxy --kubeconfig=/run/kubeconfig
root 14658 0.0 0.0 14224 880 pts/0 S+ 13:26 0:00 grep --color=auto kube

以容器方式启动的各个组件

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
fe8cb027820d gcr.io/google_containers/kube-proxy-amd64:v1.5.4 "kube-proxy --kube..." About an hour ago Up About an hour k8s_kube-proxy.f7c0b53a_kube-proxy-hz20c_kube-system_61d0bb98-0dea-11e7-bc5c-001c4297532a_f9cc7706
9cd5828d28a3 gcr.io/google_containers/pause-amd64:3.0 "/pause" About an hour ago Up About an hour k8s_POD.d8dbe16c_kube-proxy-hz20c_kube-system_61d0bb98-0dea-11e7-bc5c-001c4297532a_28af414a
60b8f173f012 gcr.io/google_containers/kube-discovery-amd64:1.0 "/usr/local/bin/ku..." About an hour ago Up About an hour k8s_kube-discovery.3779cb59_kube-discovery-1769846148-kqb1x_kube-system_5419f72e-0dea-11e7-bc5c-001c4297532a_463dc1ad
19d3bf10369d gcr.io/google_containers/pause-amd64:3.0 "/pause" About an hour ago Up About an hour k8s_POD.d8dbe16c_kube-discovery-1769846148-kqb1x_kube-system_5419f72e-0dea-11e7-bc5c-001c4297532a_2c04d6c8
8d65a04af9bd gcr.io/google_containers/pause-amd64:3.0 "/pause" About an hour ago Up About an hour k8s_dummy.f0681c27_dummy-2088944543-ctnqh_kube-system_53801181-0dea-11e7-bc5c-001c4297532a_6058f6f7
e4680cf8734d gcr.io/google_containers/pause-amd64:3.0 "/pause" About an hour ago Up About an hour k8s_POD.d8dbe16c_dummy-2088944543-ctnqh_kube-system_53801181-0dea-11e7-bc5c-001c4297532a_95e00970
6d0ef0103edc gcr.io/google_containers/kube-controller-manager-amd64:v1.5.4 "kube-controller-m..." About an hour ago Up About an hour k8s_kube-controller-manager.9a35b2e8_kube-controller-manager-dev-master-01_kube-system_04aa781520126ecd226bff8cb5e8f11a_0eef3909
f592f0cd853d gcr.io/google_containers/kube-apiserver-amd64:v1.5.4 "kube-apiserver --..." About an hour ago Up About an hour k8s_kube-apiserver.3d6f374_kube-apiserver-dev-master-01_kube-system_c7b047fbcc13d76494cea24a2ad9a1ba_f1d0d4a1
08ced03e0141 gcr.io/google_containers/kube-scheduler-amd64:v1.5.4 "kube-scheduler --..." About an hour ago Up About an hour k8s_kube-scheduler.1a2dd753_kube-scheduler-dev-master-01_kube-system_1af062e8f950e8085a65134d9d314b76_537f210b
f5f1eb371488 gcr.io/google_containers/etcd-amd64:3.0.14-kubeadm "etcd --listen-cli..." About an hour ago Up About an hour k8s_etcd.c323986f_etcd-dev-master-01_kube-system_3a26566bb004c61cd05382212e3f978f_3ffb0064
c43f82a7ef1c gcr.io/google_containers/pause-amd64:3.0 "/pause" About an hour ago Up About an hour k8s_POD.d8dbe16c_kube-controller-manager-dev-master-01_kube-system_04aa781520126ecd226bff8cb5e8f11a_166b1b6a
e8aeabbf4beb gcr.io/google_containers/pause-amd64:3.0 "/pause" About an hour ago Up About an hour k8s_POD.d8dbe16c_kube-apiserver-dev-master-01_kube-system_c7b047fbcc13d76494cea24a2ad9a1ba_993bfda3
6a7cbc9f0739 gcr.io/google_containers/pause-amd64:3.0 "/pause" About an hour ago Up About an hour k8s_POD.d8dbe16c_etcd-dev-master-01_kube-system_3a26566bb004c61cd05382212e3f978f_6f7d0263
1c2348c77a9b gcr.io/google_containers/pause-amd64:3.0 "/pause" About an hour ago Up About an hour k8s_POD.d8dbe16c_kube-scheduler-dev-master-01_kube-system_1af062e8f950e8085a65134d9d314b76_e6907a26

不过这些核心组件并不是跑在pod network中的,而是采用了host network。

1
2
3
4
5
6
7
8
9
10
11
$ kubectl get pod  --all-namespaces -o wide

NAMESPACE NAME READY STATUS RESTARTS AGE IP NODE
kube-system dummy-2088944543-ctnqh 1/1 Running 0 1h 10.211.55.11 dev-master-01
kube-system etcd-dev-master-01 1/1 Running 1 2h 10.211.55.11 dev-master-01
kube-system kube-apiserver-dev-master-01 1/1 Running 0 2h 10.211.55.11 dev-master-01
kube-system kube-controller-manager-dev-master-01 1/1 Running 0 2h 10.211.55.11 dev-master-01
kube-system kube-discovery-1769846148-kqb1x 1/1 Running 0 1h 10.211.55.11 dev-master-01
kube-system kube-dns-2924299975-8r4st 0/4 ContainerCreating 0 1h <none> dev-master-01
kube-system kube-proxy-hz20c 1/1 Running 0 1h 10.211.55.11 dev-master-01
kube-system kube-scheduler-dev-master-01 1/1 Running 0 2h 10.211.55.11 dev-master-01

安装flannel pod网络

Kubernetes一共提供五种网络组件,可以根据自己的需要选择。要使用Flannel网络,因此我们需要执行如下安装命令:

1
2
3
4
5
$ kubectl apply -f  https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml

serviceaccount "flannel" created
configmap "kube-flannel-cfg" created
daemonset "kube-flannel-ds" created

根据网络状况,安装过程需要一定的时间,最后要确保所有的Pod都处于Running状态。

稍等片刻,我们再来看master node上的cluster信息:

1
2
3
$ ps aux|grep kube|grep flannel
root 718 0.0 1.5 252216 32176 ? Ssl 15:25 0:00 /opt/bin/flanneld --ip-masq --kube-subnet-mgr
root 758 0.0 0.0 8096 1880 ? Ss 15:25 0:00 /bin/sh -c set -e -x; cp -f /etc/kube-flannel/cni-conf.json /etc/cni/net.d/10-flannel.conf; while true; do sleep 3600; done

检查各节点组件运行状态:

1
2
3
4
5
6
7
8
9
10
11
12
$ kubectl get pods --all-namespaces

NAMESPACE NAME READY STATUS RESTARTS AGE
default kube-flannel-ds-m556b 2/2 Running 3 2h
kube-system dummy-2088944543-ctnqh 1/1 Running 1 3h
kube-system etcd-dev-master-01 1/1 Running 2 4h
kube-system kube-apiserver-dev-master-01 1/1 Running 1 4h
kube-system kube-controller-manager-dev-master-01 1/1 Running 1 4h
kube-system kube-discovery-1769846148-cpf2m 1/1 Running 0 8m
kube-system kube-dns-2924299975-8r4st 4/4 Running 0 3h
kube-system kube-proxy-hz20c 1/1 Running 1 3h
kube-system kube-scheduler-dev-master-01 1/1 Running 1 4h

如果你非常想要知道它的状态及详细原因,对应你自己的NameSpace和Name把下面这条命令改一下,就可以看到详细信息了。常见的状态有RunContainerError,CrashLoopBackOff,ContainerCreating。

1
2
$ kubectl describe -n default  po kube-flannel-ds-m556b
$ kubectl describe -n kube-system po kube-dns-2924299975-8r4st

验证是否部署成功

1
2
3
$ kubectl get nodes
NAME STATUS AGE
dev-master-01 Ready,master 5h

或者访问http://localhost:8080出现这个也表示ok了。

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
$ curl http://127.0.0.1:8080
{
"paths": [
"/api",
"/api/v1",
"/apis",
"/apis/apps",
"/apis/apps/v1beta1",
"/apis/authentication.k8s.io",
"/apis/authentication.k8s.io/v1beta1",
"/apis/authorization.k8s.io",
"/apis/authorization.k8s.io/v1beta1",
"/apis/autoscaling",
"/apis/autoscaling/v1",
"/apis/batch",
"/apis/batch/v1",
"/apis/batch/v2alpha1",
"/apis/certificates.k8s.io",
"/apis/certificates.k8s.io/v1alpha1",
"/apis/extensions",
"/apis/extensions/v1beta1",
"/apis/policy",
"/apis/policy/v1beta1",
"/apis/rbac.authorization.k8s.io",
"/apis/rbac.authorization.k8s.io/v1alpha1",
"/apis/storage.k8s.io",
"/apis/storage.k8s.io/v1beta1",
"/healthz",
"/healthz/poststarthook/bootstrap-controller",
"/healthz/poststarthook/extensions/third-party-resources",
"/healthz/poststarthook/rbac/bootstrap-roles",
"/logs",
"/metrics",
"/swaggerapi/",
"/ui/",
"/version"
]

部署Kubernetes node

根据Master上初始化成功后会打印的token,把minion node加入cluster。(注意:这里要保证master node的9898端口在防火墙是打开的)

在minion node上执行

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
$ kubeadm join --token=e4f68e.6cc8c11c93148cd7 10.211.55.11 --skip-preflight-checks

[kubeadm] WARNING: kubeadm is in alpha, please do not use it for production clusters.
[preflight] Skipping pre-flight checks
[tokens] Validating provided token
[discovery] Created cluster info discovery client, requesting info from "http://10.211.55.11:9898/cluster-info/v1/?token-id=e4f68e"
[discovery] Cluster info object received, verifying signature using given token
[discovery] Cluster info signature and contents are valid, will use API endpoints [https://10.211.55.11:6443]
[bootstrap] Trying to connect to endpoint https://10.211.55.11:6443
[bootstrap] Detected server version: v1.5.4
[bootstrap] Successfully established connection with endpoint "https://10.211.55.11:6443"
[csr] Created API client to obtain unique certificate for this node, generating keys and certificate signing request
[csr] Received signed certificate from the API server:
Issuer: CN=kubernetes | Subject: CN=system:node:dev-node-01 | CA: false
Not before: 2017-03-21 09:19:00 +0000 UTC Not After: 2018-03-21 09:19:00 +0000 UTC
[csr] Generating kubelet configuration
[kubeconfig] Wrote KubeConfig file to disk: "/etc/kubernetes/kubelet.conf"

Node join complete:
* Certificate signing request sent to master and response
received.
* Kubelet informed of new secure connection details.

Run 'kubectl get nodes' on the master to see this machine join.

验证是否加入成功

加入节点后,可以在master上验证下相关信息。

1
2
3
4
5
$ kubectl get nodes

NAME STATUS AGE
dev-master-01 Ready,master 5h
dev-node-01 Ready 1m

上述这样以来基础环境就搭好了。不过只不过是万里长征第一步,折腾才刚刚开始而已。颤抖吧,少年!

一些小技巧

  • 由于使用kubeadm安装的kubernetes核心组件都是以docker容器的形式运行,如果安装过程出现问题,需要先执行下面的命令清理之前的执行残留后,才能重新开始。

kubeadm会自动检查当前环境是否有上次命令执行的“残留”。如果有,必须清理后再行执行init。我们可以通过”kubeadm reset”来清理环境,以备重来。

1
2
3
4
5
6
7
8
$ sudo kubeadm reset
[preflight] Running pre-flight checks
[reset] Stopping the kubelet service
[reset] Unmounting mounted directories in "/var/lib/kubelet"
[reset] Removing kubernetes-managed containers
[reset] Deleting contents of stateful directories: [/var/lib/kubelet /etc/cni/net.d /var/lib/etcd]
[reset] Deleting contents of config directories: [/etc/kubernetes/manifests /etc/kubernetes/pki]
[reset] Deleting files: [/etc/kubernetes/admin.conf /etc/kubernetes/kubelet.conf]
  • 如果容器部署过程中失败,你非常想要知道它的状态及详细原因。可使用如下指令:
1
2
$ kubectl describe -n default  po kube-flannel-ds-m556b
$ kubectl describe -n kube-system po kube-dns-2924299975-8r4st

参考文档

http://www.google.com
http://t.cn/RIBS5ji
http://www.jianshu.com/p/a05a2f778324
http://www.jianshu.com/p/602c5bdbbd4d
http://blog.frognew.com/2017/01/install-kubernetes-with-kubeadm.html
https://jicki.me/2016/12/13/kubernetes-1.5.0/