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本篇內容主要講解“Flannel怎么配置”，感興趣的朋友不妨來看看。本文介紹的方法操作簡單快捷，實用性強。下面就讓小編來帶大家學習“Flannel怎么配置”吧!
目前最新版的Flannel v0.10.0的命令行配置及說明如下：
Usage: /opt/bin/flanneld [OPTION]... -etcd-cafile string SSL Certificate Authority file used to secure etcd communication -etcd-certfile string SSL certification file used to secure etcd communication -etcd-endpoints string a comma-delimited list of etcd endpoints (default "http://127.0.0.1:4001,http://127.0.0.1:2379") -etcd-keyfile string SSL key file used to secure etcd communication -etcd-password string password for BasicAuth to etcd -etcd-prefix string etcd prefix (default "/coreos.com/network") -etcd-username string username for BasicAuth to etcd -healthz-ip string the IP address for healthz server to listen (default "0.0.0.0") -healthz-port int the port for healthz server to listen(0 to disable) -iface value interface to use (IP or name) for inter-host communication. Can be specified multiple times to check each option in order. Returns the first match found. -iface-regex value regex expression to match the first interface to use (IP or name) for inter-host communication. Can be specified multiple times to check each regex in order. Returns the first match found. Regexes are checked after specific interfaces specified by the iface option have already been checked. -ip-masq setup IP masquerade rule for traffic destined outside of overlay network -kube-api-url string Kubernetes API server URL. Does not need to be specified if flannel is running in a pod. -kube-subnet-mgr contact the Kubernetes API for subnet assignment instead of etcd. -kubeconfig-file string kubeconfig file location. Does not need to be specified if flannel is running in a pod. -log_backtrace_at value when logging hits line file:N, emit a stack trace -public-ip string IP accessible by other nodes for inter-host communication -subnet-file string filename where env variables (subnet, MTU, ... ) will be written to (default "/run/flannel/subnet.env") -subnet-lease-renew-margin int subnet lease renewal margin, in minutes, ranging from 1 to 1439 (default 60) -v value log level for V logs -version print version and exit -vmodule value comma-separated list of pattern=N settings for file-filtered logging
需要說明如下：
我們是通過-kube-subnet-mgr配置Flannel從Kubernetes APIServer中讀取對應的ConfigMap來獲取配置的。-kubeconfig-file, -kube-api-url我們也沒有配置，因為我們是使用DaemonSet通過Pod來部署的Flannel，所以Flannel與Kubernetes APIServer是通過ServiceAccount來認證通信的。
另外一種方式是直接從etcd中讀取Flannel配置，需要配置對應的-etcd開頭的Flag。
-subnet-file默認為/run/flannel/subnet.env,一般無需改動。Flannel會將本機的subnet信息對應的環境變量注入到該文件中，Flannel真正是從這里獲取subnet信息的,比如：
FLANNEL_NETWORK=10.244.0.0/16 FLANNEL_SUBNET=10.244.26.1/24 FLANNEL_MTU=1500 FLANNEL_IPMASQ=true
-subnet-lease-renew-margin表示etcd租約到期前多少時間就可以重新自動續約，默認是1h。因為ttl時間是24h，所以這項配置自然不允許超過24h，即[1, 1439] min.
上面的命令行配置項，都可以通過改成大寫，下劃線變中劃線，再加上FLANNELD_前綴轉成對應的環境變量的形式來設置。
比如--etcd-endpoints=http://10.0.0.2:2379對應的環境變量為FLANNELD_ETCD_ENDPOINTS=http://10.0.0.2:2379。
通過Kubernetes DaemonSet部署Flannel，這一點毫無爭議。同時創建對應的ClusterRole，ClusterRoleBinding，ServiceAccount，ConfigMap。完整的Yaml描述文件可參考如下：
---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
name: flannel
rules:
- apiGroups:
- ""
resources:
- pods
verbs:
- get
- apiGroups:
- ""
resources:
- nodes
verbs:
- list
- watch
- apiGroups:
- ""
resources:
- nodes/status
verbs:
- patch
---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
name: flannel
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: flannel
subjects:
- kind: ServiceAccount
name: flannel
namespace: kube-system
---
apiVersion: v1
kind: ServiceAccount
metadata:
name: flannel
namespace: kube-system
---
apiVersion: v1
kind: ConfigMap
metadata:
name: kube-flannel-cfg
namespace: kube-system
labels:
tier: node
k8s-app: flannel
data:
cni-conf.json: |
{
"name": "cbr0",
"plugins": [
{
"type": "flannel",
"delegate": {
"hairpinMode": true,
"isDefaultGateway": true
}
}
]
}
net-conf.json: |
{
"Network": "10.244.0.0/16",
"Backend": {
"Type": "host-gw"
}
}
---
apiVersion: extensions/v1beta1
kind: DaemonSet
metadata:
name: kube-flannel
namespace: kube-system
labels:
tier: node
k8s-app: flannel
spec:
template:
metadata:
labels:
tier: node
k8s-app: flannel
spec:
imagePullSecrets:
- name: harborsecret
serviceAccountName: flannel
containers:
- name: kube-flannel
image: registry.vivo.xyz:4443/coreos/flannel:v0.10.0-amd64
command: [ "/opt/bin/flanneld", "--ip-masq", "--kube-subnet-mgr"]
securityContext:
privileged: true
env:
- name: POD_NAME
valueFrom:
fieldRef:
fieldPath: metadata.name
- name: POD_NAMESPACE
valueFrom:
fieldRef:
fieldPath: metadata.namespace
- name: POD_IP
valueFrom:
fieldRef:
fieldPath: status.podIP
volumeMounts:
- name: run
mountPath: /run
- name: cni
mountPath: /etc/cni/net.d
- name: flannel-cfg
mountPath: /etc/kube-flannel/
- name: install-cni
image: registry.vivo.xyz:4443/coreos/flannel-cni:v0.3.0
command: ["/install-cni.sh"]
#command: ["sleep","10000"]
env:
# The CNI network config to install on each node.
- name: CNI_NETWORK_CONFIG
valueFrom:
configMapKeyRef:
name: kube-flannel-cfg
key: cni-conf.json
volumeMounts:
#- name: cni
# mountPath: /etc/cni/net.d
- name: cni
mountPath: /host/etc/cni/net.d
- name: host-cni-bin
mountPath: /host/opt/cni/bin/
hostNetwork: true
tolerations:
- key: node-role.kubernetes.io/master
operator: Exists
effect: NoSchedule
volumes:
- name: run
hostPath:
path: /run
#- name: cni
# hostPath:
# path: /etc/kubernetes/cni/net.d
- name: cni
hostPath:
path: /etc/cni/net.d
- name: flannel-cfg
configMap:
name: kube-flannel-cfg
- name: host-cni-bin
hostPath:
path: /etc/cni/net.d
updateStrategy:
rollingUpdate:
maxUnavailable: 1
type: RollingUpdate很容易混淆幾個東西。我們通常說的Flannel（coreos/flannel），其實說的是flanneld。大家都知道Kubernetes是通過CNI標準對接網絡插件的，但是當你去看Flannel（coreos/flannel）的代碼時，并沒有發現它實現了CNI的接口。如果你玩過其他CNI插件，你會知道還有一個二進制文件用來供kubele調用，并且會調用后端的網絡插件。對于Flannel（coreos/flannel）來說，這個二進制文件是什么呢？git repo在哪里呢？
這個二進制文件就對應宿主機的/etc/cni/net.d/flannel，它的代碼地址是https://github.com/containernetworking/plugins，最可恨的它的名字就叫做flannel，為啥不類似contiv netplugin對應的contivk8s一樣，取名flannelk8s之類的。
上面的Flannel Pod中還有一個容器叫做install-cni，它對應的腳本在https://github.com/coreos/flannel-cni。
/opt/bin/flanneld --> https://github.com/coreos/flannel
/etc/cni/net.d/flannel --> https://github.com/containernetworking/plugins
/install-cni.sh --> https://github.com/coreos/flannel-cni
在kube-flannel容器里面運行的是我們的主角flanneld，我們需要關注的這個容器里面的目錄/文件：
/etc/kube-flannel/cni-conf.json
/etc/kube-flannel/net-conf.json
/run/flannel/subnet.env
/opt/bin/flanneld
下面是我的環境對應的內容：
/run/flannel # ls /etc/kube-flannel/
cni-conf.json net-conf.json
/run/flannel # cat /etc/kube-flannel/cni-conf.json
{
"name": "cbr0",
"plugins": [
{
"type": "flannel",
"delegate": {
"hairpinMode": true,
"isDefaultGateway": true
}
}
]
}
/run/flannel # cat /etc/kube-flannel/net-conf.json
{
"Network": "10.244.0.0/16",
"Backend": {
"Type": "host-gw"
}
}
/run/flannel # cat /run/flannel/subnet.env
FLANNEL_NETWORK=10.244.0.0/16
FLANNEL_SUBNET=10.244.26.1/24
FLANNEL_MTU=1500
FLANNEL_IPMASQ=true
/run/flannel # ls /opt/bin/
flanneld mk-docker-opts.sh
/run/flannel # cat /opt/bin/mk-docker-opts.sh
#!/bin/sh
usage() {
echo "$0 [-f FLANNEL-ENV-FILE] [-d DOCKER-ENV-FILE] [-i] [-c] [-m] [-k COMBINED-KEY]
Generate Docker daemon options based on flannel env file
OPTIONS:
-f Path to flannel env file. Defaults to /run/flannel/subnet.env
-d Path to Docker env file to write to. Defaults to /run/docker_opts.env
-i Output each Docker option as individual var. e.g. DOCKER_OPT_MTU=1500
-c Output combined Docker options into DOCKER_OPTS var
-k Set the combined options key to this value (default DOCKER_OPTS=)
-m Do not output --ip-masq (useful for older Docker version)
" >&2
exit 1
}
flannel_env="/run/flannel/subnet.env"
docker_env="/run/docker_opts.env"
combined_opts_key="DOCKER_OPTS"
indiv_opts=false
combined_opts=false
ipmasq=true
while getopts "f:d:icmk:?h" opt; do
case $opt in
f)
flannel_env=$OPTARG
;;
d)
docker_env=$OPTARG
;;
i)
indiv_opts=true
;;
c)
combined_opts=true
;;
m)
ipmasq=false
;;
k)
combined_opts_key=$OPTARG
;;
[\?h])
usage
;;
esac
done
if [ $indiv_opts = false ] && [ $combined_opts = false ]; then
indiv_opts=true
combined_opts=true
fi
if [ -f "$flannel_env" ]; then
. $flannel_env
fi
if [ -n "$FLANNEL_SUBNET" ]; then
DOCKER_OPT_BIP="--bip=$FLANNEL_SUBNET"
fi
if [ -n "$FLANNEL_MTU" ]; then
DOCKER_OPT_MTU="--mtu=$FLANNEL_MTU"
fi
if [ -n "$FLANNEL_IPMASQ" ] && [ $ipmasq = true ] ; then
if [ "$FLANNEL_IPMASQ" = true ] ; then
DOCKER_OPT_IPMASQ="--ip-masq=false"
elif [ "$FLANNEL_IPMASQ" = false ] ; then
DOCKER_OPT_IPMASQ="--ip-masq=true"
else
echo "Invalid value of FLANNEL_IPMASQ: $FLANNEL_IPMASQ" >&2
exit 1
fi
fi
eval docker_opts="\$${combined_opts_key}"
if [ "$docker_opts" ]; then
docker_opts="$docker_opts ";
fi
echo -n "" >$docker_env
for opt in $(set | grep "DOCKER_OPT_"); do
OPT_NAME=$(echo $opt | awk -F "=" '{print $1;}');
OPT_VALUE=$(eval echo "\$$OPT_NAME");
if [ "$indiv_opts" = true ]; then
echo "$OPT_NAME=\"$OPT_VALUE\"" >>$docker_env;
fi
docker_opts="$docker_opts $OPT_VALUE";
done
if [ "$combined_opts" = true ]; then
echo "${combined_opts_key}=\"${docker_opts}\"" >>$docker_env
fiinstall-cni容器顧名思義就是負責安裝cni插件的，把鏡像里的flannel等二進制文件復制到宿主機的/etc/cni/net.d，注意這個目錄要匹配kubelet對應的cni配置項，如果你沒改kubelet默認配置，那么kubelet默認也是配置的這個cni目錄。我們需要關注install-cni容器內的目錄/文件：
/host/etc/cni/net.d/
/host/opt/cni/bin/
/host/etc/cni/net.d/10-flannel.conflist
下面是我的環境對應的內容：
/host/etc/cni/net.d # pwd
/host/etc/cni/net.d
/host/etc/cni/net.d # ls
10-flannel.conflist dhcp ipvlan noop tuning
bridge flannel loopback portmap vlan
cnitool host-local macvlan ptp
/host/etc/cni/net.d # cd /host/opt/cni/bin/
/host/opt/cni/bin # ls
10-flannel.conflist dhcp ipvlan noop tuning
bridge flannel loopback portmap vlan
cnitool host-local macvlan ptp
/opt/cni/bin # ls
bridge dhcp host-local loopback noop ptp vlan
cnitool flannel ipvlan macvlan portmap tuning
/opt/cni/bin # cat /host/etc/cni/net.d/10-flannel.conflist
{
"name": "cbr0",
"plugins": [
{
"type": "flannel",
"delegate": {
"hairpinMode": true,
"isDefaultGateway": true
}
}
]
}畫一個圖，應該就很清晰了。注意帶顏色的部分是Volume對應的信息，可重點關注。
創建容器網絡的流程就是：kubelet ——> flannel ——> flanneld。如果宿主機上并發創建Pod，則你會看到有多個flannel進程在后臺，不過正常幾秒鐘就會結束，而flanneld是常駐進程。
Openshift默認也是使用Flannel host-gw容器網絡方案，其官網也清晰的畫出了host-gw的data flow diagram：
Node 1中對應的ip routes：
default via 192.168.0.100 dev eth0 proto static metric 100 10.1.15.0/24 dev docker0 proto kernel scope link src 10.1.15.1 10.1.20.0/24 via 192.168.0.200 dev eth0
Node 2中對應的ip routes：
default via 192.168.0.200 dev eth0 proto static metric 100 10.1.20.0/24 dev docker0 proto kernel scope link src 10.1.20.1 10.1.15.0/24 via 192.168.0.100 dev eth0
在我的集群中是使用kube-subnet-mgr來管理subnet的，而不是直接通過etcd v2來管理的。
flanneld啟動時，需要對應Node上已經配置好PodCIDR，可通過get node信息查看.spec.PodCIDR字段是否有值。
配置Node的CIDR可有兩種方式：
手動配置每個Node上kubelet的--pod-cidr；
配置kube-controller-manager的--allocate-node-cidrs=true --cluster-cidr=xx.xx.xx.xx/yy，由CIDR Controller自動給每個節點配置PodCIDR。
另外，你還會發現每個Node都被打上了很多flannel開頭的Annotation，這些Annotation會在每次flanneld啟動時RegisterNetwork的時候進行更新。這些Annotation主要用于Node Lease。
flannel.alpha.coreos.com/backend-data: "null"
flannel.alpha.coreos.com/backend-type: host-gw
flannel.alpha.coreos.com/kube-subnet-manager: "true"
flannel.alpha.coreos.com/public-ip: xx.xx.xx.xx
flannel.alpha.coreos.com/public-ip-overwrite:yy.yy.yy.yy (ps:optional)
下面是我的環境中某個節點的信息：
# kubectl get no 10.21.36.79 -o yaml apiVersion: v1 kind: Node metadata: annotations: flannel.alpha.coreos.com/backend-data: "null" flannel.alpha.coreos.com/backend-type: host-gw flannel.alpha.coreos.com/kube-subnet-manager: "true" flannel.alpha.coreos.com/public-ip: 10.21.36.79 node.alpha.kubernetes.io/ttl: "0" volumes.kubernetes.io/controller-managed-attach-detach: "true" creationTimestamp: 2018-02-09T07:18:06Z labels: beta.kubernetes.io/arch: amd64 beta.kubernetes.io/os: linux kubernetes.io/hostname: 10.21.36.79 name: 10.21.36.79 resourceVersion: "45074326" selfLink: /api/v1/nodes/10.21.36.79 uid: 5f91765e-0d69-11e8-88cb-f403434bff24 spec: externalID: 10.21.36.79 podCIDR: 10.244.29.0/24 status: addresses: - address: 10.21.36.79 type: InternalIP - address: 10.21.36.79 type: Hostname allocatable: alpha.kubernetes.io/nvidia-gpu: "0" cpu: "34" memory: 362301176Ki pods: "200" capacity: alpha.kubernetes.io/nvidia-gpu: "0" cpu: "40" memory: 395958008Ki pods: "200" conditions: - lastHeartbeatTime: 2018-02-27T14:07:30Z lastTransitionTime: 2018-02-13T13:05:57Z message: kubelet has sufficient disk space available reason: KubeletHasSufficientDisk status: "False" type: OutOfDisk - lastHeartbeatTime: 2018-02-27T14:07:30Z lastTransitionTime: 2018-02-13T13:05:57Z message: kubelet has sufficient memory available reason: KubeletHasSufficientMemory status: "False" type: MemoryPressure - lastHeartbeatTime: 2018-02-27T14:07:30Z lastTransitionTime: 2018-02-13T13:05:57Z message: kubelet has no disk pressure reason: KubeletHasNoDiskPressure status: "False" type: DiskPressure - lastHeartbeatTime: 2018-02-27T14:07:30Z lastTransitionTime: 2018-02-13T13:05:57Z message: kubelet is posting ready status reason: KubeletReady status: "True" type: Ready daemonEndpoints: kubeletEndpoint: Port: 10250 images: - names: - registry.vivo.xyz:4443/bigdata_release/tensorflow1.5.0@sha256:6d61595c8e85d3724ec42298f8f97cdc782c5d83dd8f651c2eb037c25f525071 - registry.vivo.xyz:4443/bigdata_release/tensorflow1.5.0:v2.0 sizeBytes: 3217838862 - names: - registry.vivo.xyz:4443/bigdata_release/tensorflow1.3.0@sha256:d14b7776578e3e844bab203b17ae504a0696038c7106469504440841ce17e85f - registry.vivo.xyz:4443/bigdata_release/tensorflow1.3.0:v1.9 sizeBytes: 2504726638 - names: - registry.vivo.xyz:4443/coreos/flannel-cni@sha256:dc5b5b370700645efcacb1984ae1e48ec9e297acbb536251689a239f13d08850 - registry.vivo.xyz:4443/coreos/flannel-cni:v0.3.0 sizeBytes: 49786179 - names: - registry.vivo.xyz:4443/coreos/flannel@sha256:2a1361c414acc80e00514bc7abdbe0cd3dc9b65a181e5ac7393363bcc8621f39 - registry.vivo.xyz:4443/coreos/flannel:v0.10.0-amd64 sizeBytes: 44577768 - names: - registry.vivo.xyz:4443/google_containers/pause-amd64@sha256:3b3a29e3c90ae7762bdf587d19302e62485b6bef46e114b741f7d75dba023bd3 - registry.vivo.xyz:4443/google_containers/pause-amd64:3.0 sizeBytes: 746888 nodeInfo: architecture: amd64 bootID: bc7a36a4-2d9b-4caa-b852-445a5fb1b0b9 containerRuntimeVersion: docker://1.12.6 kernelVersion: 3.10.0-514.el7.x86_64 kubeProxyVersion: v1.7.4+793658f2d7ca7 kubeletVersion: v1.7.4+793658f2d7ca7 machineID: edaf7dacea45404b9b3cfe053181d317 operatingSystem: linux osImage: CentOS Linux 7 (Core) systemUUID: 30393137-3136-4336-5537-3335444C4C30
到此，相信大家對“Flannel怎么配置”有了更深的了解，不妨來實際操作一番吧！這里是億速云網站，更多相關內容可以進入相關頻道進行查詢，關注我們，繼續學習！
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