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增加flanneld安装详细步骤

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Jimmy Song 2017-04-17 17:30:19 +08:00
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06-部署node节点.md
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@ -24,6 +24,8 @@ apiserver bootstrap.kubeconfig config controller-manager kubelet kube-proxy
参考我之前写的文章[Kubernetes基于Flannel的网络配置](http://rootsongjc.github.io/blogs/kubernetes-network-config/)，之前没有配置TLS，现在需要在serivce配置文件中增加TLS配置。
直接使用yum安装flanneld即可。
service配置文件`/usr/lib/systemd/system/flanneld.service`。
```ini
@ -66,6 +68,126 @@ FLANNEL_OPTIONS="-etcd-cafile=/etc/kubernetes/ssl/ca.pem -etcd-certfile=/etc/kub
在FLANNEL_OPTIONS中增加TLS的配置。
**在etcd中创建网络配置**
执行下面的命令为docker分配IP地址段。
```shell
etcdctl --endpoints=https://172.20.0.113:2379,https://172.20.0.114:2379,https://172.20.0.115:2379 \
--ca-file=/etc/kubernetes/ssl/ca.pem \
--cert-file=/etc/kubernetes/ssl/kubernetes.pem \
--key-file=/etc/kubernetes/ssl/kubernetes-key.pem \
mkdir /kube-centos/network
etcdctl --endpoints=https://172.20.0.113:2379,https://172.20.0.114:2379,https://172.20.0.115:2379 \
--ca-file=/etc/kubernetes/ssl/ca.pem \
--cert-file=/etc/kubernetes/ssl/kubernetes.pem \
--key-file=/etc/kubernetes/ssl/kubernetes-key.pem \
mk /kube-centos/network/config "{ \"Network\": \"172.30.0.0/16\", \"SubnetLen\": 24, \"Backend\": { \"Type\": \"vxlan\" } }"
```
**配置Docker**
Flannel的[文档](https://github.com/coreos/flannel/blob/master/Documentation/running.md)中有写**Docker Integration**：
Docker daemon accepts `--bip` argument to configure the subnet of the docker0 bridge. It also accepts `--mtu` to set the MTU for docker0 and veth devices that it will be creating. Since flannel writes out the acquired subnet and MTU values into a file, the script starting Docker can source in the values and pass them to Docker daemon:
```
source /run/flannel/subnet.env
docker daemon --bip=${FLANNEL_SUBNET} --mtu=${FLANNEL_MTU} &
```
Systemd users can use `EnvironmentFile` directive in the .service file to pull in `/run/flannel/subnet.env`
如果你不是使用yum安装的flanneld，那么需要下载flannel github release中的tar包，解压后会获得一个**mk-docker-opts.sh**文件。
这个文件是用来`Generate Docker daemon options based on flannel env file`。
执行`./mk-docker-opts.sh -i`将会生成如下两个文件环境变量文件。
/run/flannel/subnet.env
```
FLANNEL_NETWORK=172.30.0.0/16
FLANNEL_SUBNET=172.30.46.1/24
FLANNEL_MTU=1450
FLANNEL_IPMASQ=false
```
/run/docker_opts.env
```
DOCKER_OPT_BIP="--bip=172.30.46.1/24"
DOCKER_OPT_IPMASQ="--ip-masq=true"
DOCKER_OPT_MTU="--mtu=1450"
```
现在查询etcd中的内容可以看到：
```
$etcdctl --endpoints=${ETCD_ENDPOINTS} \
--ca-file=/etc/kubernetes/ssl/ca.pem \
--cert-file=/etc/kubernetes/ssl/kubernetes.pem \
--key-file=/etc/kubernetes/ssl/kubernetes-key.pem \
ls /kube-centos/network/subnets
/kube-centos/network/subnets/172.30.14.0-24
/kube-centos/network/subnets/172.30.38.0-24
/kube-centos/network/subnets/172.30.46.0-24
$etcdctl --endpoints=${ETCD_ENDPOINTS} \
--ca-file=/etc/kubernetes/ssl/ca.pem \
--cert-file=/etc/kubernetes/ssl/kubernetes.pem \
--key-file=/etc/kubernetes/ssl/kubernetes-key.pem \
get /kube-centos/network/config
{ "Network": "172.30.0.0/16", "SubnetLen": 24, "Backend": { "Type": "vxlan" } }
$etcdctl get /kube-centos/network/subnets/172.30.14.0-24
{"PublicIP":"172.20.0.114","BackendType":"vxlan","BackendData":{"VtepMAC":"56:27:7d:1c:08:22"}}
$etcdctl get /kube-centos/network/subnets/172.30.38.0-24
{"PublicIP":"172.20.0.115","BackendType":"vxlan","BackendData":{"VtepMAC":"12:82:83:59:cf:b8"}}
$etcdctl get /kube-centos/network/subnets/172.30.46.0-24
{"PublicIP":"172.20.0.113","BackendType":"vxlan","BackendData":{"VtepMAC":"e6:b2:fd:f6:66:96"}}
```
**设置docker0网桥的IP地址**
```shell
source /run/flannel/subnet.env
ifconfig docker0 $FLANNEL_SUBNET
```
这样docker0和flannel网桥会在同一个子网中，如
```
6: docker0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN
link/ether 02:42:da:bf:83:a2 brd ff:ff:ff:ff:ff:ff
inet 172.30.38.1/24 brd 172.30.38.255 scope global docker0
valid_lft forever preferred_lft forever
7: flannel.1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1450 qdisc noqueue state UNKNOWN
link/ether 9a:29:46:61:03:44 brd ff:ff:ff:ff:ff:ff
inet 172.30.38.0/32 scope global flannel.1
valid_lft forever preferred_lft forever
```
现在就可以重启docker了。
重启了docker后还要重启kubelet，这时又遇到问题，kubelet启动失败。报错：
```
Mar 31 16:44:41 sz-pg-oam-docker-test-002.tendcloud.com kubelet[81047]: error: failed to run Kubelet: failed to create kubelet: misconfiguration: kubelet cgroup driver: "cgroupfs" is different from docker cgroup driver: "systemd"
```
这是kubelet与docker的**cgroup driver**不一致导致的，kubelet启动的时候有个`—cgroup-driver`参数可以指定为"cgroupfs"或者“systemd”。
```
--cgroup-driver string Driver that the kubelet uses to manipulate cgroups on the host. Possible values: 'cgroupfs', 'systemd' (default "cgroupfs")
```
**启动flannel**
```shell
systemctl daemon-reload
systemctl start flanneld
systemctl status flanneld
```
## 安装和配置 kubelet
kubelet 启动时向 kube-apiserver 发送 TLS bootstrapping 请求，需要先将 bootstrap token 文件中的 kubelet-bootstrap 用户赋予 system:node-bootstrapper cluster 角色(role)，