kube-controller-manager CIDR allocation failed

查看kube-controller-manager 报错， 说ip地址段已经没有可用的ip了

[root@master1 ~]# journalctl  -f -t kube-controller-manager
-- Logs begin at 日 2021-09-12 12:29:49 CST. --
9月 23 13:26:43 master1 kube-controller-manager[1282]: E0923 13:26:43.273721    1282 controller_utils.go:260] Error while processing Node Add/Delete: failed to allocate cidr from cluster cidr at idx:0: CIDR allocation failed; there are no remaining CIDRs left to allocate in the accepted range
9月 23 13:26:43 master1 kube-controller-manager[1282]: I0923 13:26:43.273889    1282 event.go:291] "Event occurred" object="master1" kind="Node" apiVersion="v1" type="Normal" reason="CIDRNotAvailable" message="Node master1 status is now: CIDRNotAvailable"
9月 23 13:26:58 master1 kube-controller-manager[1282]: I0923 13:26:58.086189    1282 controller_utils.go:185] Recording status change CIDRNotAvailable event message for node node2
9月 23 13:26:58 master1 kube-controller-manager[1282]: E0923 13:26:58.086245    1282 controller_utils.go:260] Error while processing Node Add/Delete: failed to allocate cidr from cluster cidr at idx:0: CIDR allocation failed; there are no remaining CIDRs left to allocate in the accepted range
9月 23 13:26:58 master1 kube-controller-manager[1282]: I0923 13:26:58.086424    1282 event.go:291] "Event occurred" object="node2" kind="Node" apiVersion="v1" type="Normal" reason="CIDRNotAvailable" message="Node node2 status is now: CIDRNotAvailable"9月 23 13:27:08 master1 kube-controller-manager[1282]: I0923 13:27:08.463702    1282 controller_utils.go:185] Recording status change CIDRNotAvailable event message for node master2
9月 23 13:27:08 master1 kube-controller-manager[1282]: E0923 13:27:08.463757    1282 controller_utils.go:260] Error while processing Node Add/Delete: failed to allocate cidr from cluster cidr at idx:0: CIDR allocation failed; there are no remaining CIDRs left to allocate in the accepted range
9月 23 13:27:08 master1 kube-controller-manager[1282]: I0923 13:27:08.464029    1282 event.go:291] "Event occurred" object="master2" kind="Node" apiVersion="v1" type="Normal" reason="CIDRNotAvailable" message="Node master2 status is now: CIDRNotAvailable"

kube-controller-manager 配置文件中， 修改cluster-cidr 使用了一个C

[Service]
ExecStart=/usr/local/bin/kube-controller-manager 
--leader-elect=true 
--kubeconfig=/etc/kubernetes/kube-controller-manager.kubeconfig 
--bind-address=192.168.15.131 
--allocate-node-cidrs=true 
--cluster-cidr=192.168.56.0/24 --secure-port=10257 

kube-controller-manager 分配pod网段， 默认每个node上的pod都会分配一个C段， 如果只有一个，那么需要设置子网--node-cidr-mask-size
k8s集群中使用了7台服务器搭建，  那么需要 254/7 子网为27位， 每台机器上分配30个IP

修改 kube-controller-manager 配置文件，添加红色部分

[Service]
ExecStart=/usr/local/bin/kube-controller-manager 
--leader-elect=true 
--kubeconfig=/etc/kubernetes/kube-controller-manager.kubeconfig 
--bind-address=192.168.15.131 
--allocate-node-cidrs=true 
--cluster-cidr=192.168.56.0/24 
--node-cidr-mask-size-ipv4=27 
--secure-port=10257 

重启 kube-controller-manager

systemctl daemon-reload
systemctl restart kube-controller-manager