使用F5与Openshift集成目的

外部流量访问应用时，通过F5 BIG-IP硬件设备直接代理到集群中的Pod。
这样做的好处，很明显。

  • 使用硬件负载均衡器替换掉软件负载均衡器，提高性能。
  • F5有更灵活的配置，可以实现更复杂的流量控制

Openshift操作

Openshift通过BIG-IP Controller来控制BIG-IP设备。由于Openshift是基于Kubernetes的，所以它们使用同一个Controller（k8s-bigip-ctlr）。BIG-IP Controller为集群中的应用配置BIG-IP对象，提供南北流量的服务。

F5集成Openshift原理图
BIG-IP Controller有两种方式来使用F5 BIG-IP设备

  • 为Openshift中的Service提供代理流量
  • 为Openshift中的Route提供代理流量

为Openshift中的Service提供代理流量_(不介绍具体部署操作)_

这种方式，我们测试下来发现，需要为对外提供服务的Service绑定到F5的不同端口，同时外部访问应用时需要指定端口号。如：
app1.openshift.example.com:8000, app2.openshift.example.com:8001，app3.openshift.example.com:8002，其中端口号不能重复。

  • 这种方式在真正使用时不能满足业务需求，除非在F5的前面再加一层代理，这又增加了架构的复杂性。
  • 理想的状态是，所以的App应用的HTTP请求都访问F5的80端口，而HTTPS的请求访问F5的443端口，根据请求的域名路由到对应的Pool中（每个Pool是一个Service下的所有Pod的列表）。
  • 很高兴告诉大家，第二种方式能够满足上面的需求

为Openshift中的Route提供代理流量

使用BIG-IP作为Openshift的Router，能实现以下功能：

  • 为Services创建BIG-IP本地流量规则
  • 提供HTTP/HTTPS路由
  • 为Route资源添加BIG-IP健康检查

本文只介绍，如何使用F5提供HTTP/HTTPS路由。这也是最核心的部分。

部署环境版本：
2台F5：v13 192.168.200.82 192.168.200.83
Openshift集群： v3.9.1

创建新的HostSub Openshift

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# hostsubnet.yml
apiVersion: v1
kind: HostSubnet
metadata:
  name: f5-bigip-node01
  annotations:
    pod.network.openshift.io/fixed-vnid-host: "0"
    pod.network.openshift.io/assign-subnet: "true"
# provide a name for the node that will serve as BIG-IP's entry into the cluster
host: f5-bigip-node01
# The hostIP address will be the BIG-IP interface address routable to the
# OpenShift Origin nodes.
# This address is the BIG-IP VTEP in the SDN's VXLAN.
hostIP: 192.168.200.82
---
apiVersion: v1
kind: HostSubnet
metadata:
  name: f5-bigip-node02
  annotations:
    pod.network.openshift.io/fixed-vnid-host: "0"
    pod.network.openshift.io/assign-subnet: "true"
# provide a name for the node that will serve as BIG-IP's entry into the cluster
host: f5-bigip-node02
# The hostIP address will be the BIG-IP interface address routable to the
# OpenShift Origin nodes.
# This address is the BIG-IP VTEP in the SDN's VXLAN.
hostIP: 192.168.200.83
---
apiVersion: v1
kind: HostSubnet
metadata:
  name: f5-bigip-float
  annotations:
    pod.network.openshift.io/fixed-vnid-host: "0"
    pod.network.openshift.io/assign-subnet: "true"
# provide a name for the node that will serve as BIG-IP's entry into the cluster
host: f5-bigip-float
# The hostIP address will be the BIG-IP interface address routable to the
# OpenShift Origin nodes.
# This address is the BIG-IP VTEP in the SDN's VXLAN.
hostIP: 192.168.200.84
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oc create -f hostsubnet.yml

查看执行结果

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[root@master01 ~]# oc get hostsubnet 
NAME                                 HOST                                 HOST IP         SUBNET          EGRESS IPS
f5-bigip-float                       f5-bigip-float                       192.168.200.84   10.128.6.0/23   []
f5-bigip-node01                      f5-bigip-node01                      192.168.200.82   10.129.6.0/23   []
f5-bigip-node02                      f5-bigip-node02                      192.168.200.83   10.130.4.0/23   []
master01.example.com   master01.example.com   192.168.200.1     10.130.0.0/23   []
master02.example.com   master02.example.com   192.168.200.2     10.128.0.0/23   []
master03.example.com   master03.example.com   192.168.200.3     10.128.2.0/23   []
node01.example.com     node01.example.com     192.168.200.21    10.129.0.0/23   []
node02.example.com     node02.example.com     192.168.200.22    10.131.0.0/23   []
router01.example.com   router01.example.com   192.168.200.11    10.129.2.0/23   []
router02.example.com   router02.example.com   192.168.200.12    10.130.2.0/23   []

创建一个VXLAN profile F5

在F5的TMOS终端，创建一个多点模式的vxlan

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create /net tunnels vxlan openshift_vxlan flooding-type multipoint

创建一个VXLAN Tunnel F5

Local Address使用vip： 192.168.200.84
Secondary Address使用F5的设备IP：node1 192.168.200.82， node2 192.168.200.83
在F5 Node1上的TMOS创建Tunnel

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create /net tunnels tunnel <float_tun_name> key 0 profile openshift_vxlan local-address 192.168.200.84 secondary-address 192.168.200.82 traffic-group traffic-group-1

在F5 Node2上的TMOS创建Tunnel

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create /net tunnels tunnel <float_tun_name> key 0 profile openshift_vxlan local-address 192.168.200.84 secondary-address 192.168.200.83 traffic-group traffic-group-1

在每个F5设备VXLAN中创建Self IP F5

IP为设备对应在Openshift的HostSubnet下的一个IP（只要在对应的HostSubnet下就OK）
在F5 Node1中创建Self IP

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create /net self 10.129.6.82/14 allow-service none vlan openshift_vxlan

在F5 Node2中创建Self IP

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create /net self 10.130.4.83/14 allow-service none vlan openshift_vxlan

在当前主F5设备的VXLAN下创建Floating IP F5

如：当前主F5设备为node1，那Floating IP为主设备所在的HostSubnet下。

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create /net self 10.128.6.84/14 allow-service none traffic-group traffic-group-1 vlan openshift_vxlan

创建一个新的Partition F5

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create auth partition OpenShift

创建访问F5 BIG-IP的私钥 Openshift

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oc create secret generic bigip-login --from-literal=username=admin --from-literal=password=admin -n kube-system

创建RBAC认证 Openshift

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# cluster-role.yml
apiVersion: v1
kind: ServiceAccount
metadata:
  name: bigip-ctlr
  namespace: kube-system
---
# For use in OpenShift clusters
apiVersion: v1
kind: ClusterRole
metadata:
  annotations:
    authorization.openshift.io/system-only: "true"
  name: system:bigip-ctlr
  namespace: kube-system
rules:
- apiGroups: ["", "extensions"]
  resources: ["nodes", "services", "endpoints", "namespaces", "ingresses", "routes" ]
  verbs: ["get", "list", "watch"]
- apiGroups: ["", "extensions"]
  resources: ["configmaps", "events", "ingresses/status"]
  verbs: ["get", "list", "watch", "update", "create", "patch" ]
- apiGroups: ["", "extensions"]
  resources: ["secrets"]
  resourceNames: ["bigip-login"]
  verbs: ["get", "list", "watch"]

---
apiVersion: v1
kind: ClusterRoleBinding
metadata:
  name: bigip-ctlr-role
  namespace: kube-system
userNames:
- system:serviceaccount:kube-system:bigip-ctlr
subjects:
- kind: ServiceAccount
  name: bigip-ctlr
roleRef:
  name: system:bigip-ctlr
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oc create -f cluster-role.yml

部署BIG-IP Controller Openshift

  • 对应每台F5设备创建一个Deployment
  • Deployment中的 –bigip-url 为设备的IP
  • Deployment中的 –bigip-partition为之前F5下创建的Partition,Openshift
  • Deployment中的 –route-vserver-addr 为F5对外提供服务的IP
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#deployment.yml
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: f5-bigip-ctlr-01
spec:
  replicas: 1
  template:
    metadata:
      name: k8s-bigip-ctlr
      labels:
        app: k8s-bigip-ctlr
    spec:
      # Name of the Service Account bound to a Cluster Role with the required
      # permissions
      serviceAccountName: bigip-ctlr
      containers:
        - name: k8s-bigip-ctlr
          # replace the version as needed
          image: "f5networks/k8s-bigip-ctlr:1.5.1"
          env:
            - name: BIGIP_USERNAME
              valueFrom:
                secretKeyRef:
                  # Replace with the name of the Secret containing your login
                  # credentials
                  name: bigip-login
                  key: username
            - name: BIGIP_PASSWORD
              valueFrom:
                secretKeyRef:
                  # Replace with the name of the Secret containing your login
                  # credentials
                  name: bigip-login
                  key: password
          command: ["/app/bin/k8s-bigip-ctlr"]
          args: [
            # See the k8s-bigip-ctlr documentation for information about
            # all config options
            # http://clouddocs.f5.com/products/connectors/k8s-bigip-ctlr/latest
            "--bigip-username=$(BIGIP_USERNAME)",
            "--bigip-password=$(BIGIP_PASSWORD)",
            "--bigip-url=192.168.200.82",
            "--bigip-partition=OpenShift",
            "--pool-member-type=cluster",
            "--openshift-sdn-name=/Common/openshift_vxlan",
            '--manage-routes=true',
            '--route-vserver-addr=192.168.200.80'
            ]
      imagePullSecrets:
        # Secret containing the BIG-IP system login credentials
        - name: bigip-login

---

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: f5-bigip-ctlr-02
spec:
  replicas: 1
  template:
    metadata:
      name: k8s-bigip-ctlr
      labels:
        app: k8s-bigip-ctlr
    spec:
      # Name of the Service Account bound to a Cluster Role with the required
      # permissions
      serviceAccountName: bigip-ctlr
      containers:
        - name: k8s-bigip-ctlr
          # replace the version as needed
          image: "f5networks/k8s-bigip-ctlr:1.5.1"
          env:
            - name: BIGIP_USERNAME
              valueFrom:
                secretKeyRef:
                  # Replace with the name of the Secret containing your login
                  # credentials
                  name: bigip-login
                  key: username
            - name: BIGIP_PASSWORD
              valueFrom:
                secretKeyRef:
                  # Replace with the name of the Secret containing your login
                  # credentials
                  name: bigip-login
                  key: password
          command: ["/app/bin/k8s-bigip-ctlr"]
          args: [
            # See the k8s-bigip-ctlr documentation for information about
            # all config options
            # http://clouddocs.f5.com/products/connectors/k8s-bigip-ctlr/latest
            "--bigip-username=$(BIGIP_USERNAME)",
            "--bigip-password=$(BIGIP_PASSWORD)",
            "--bigip-url=192.168.200.83",
            "--bigip-partition=OpenShift",
            "--pool-member-type=cluster",
            "--openshift-sdn-name=/Common/openshift_vxlan",
            '--manage-routes=true',
            '--route-vserver-addr=192.168.200.80'
            ]
      imagePullSecrets:
        - name: bigip-login
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oc create -f deployment.yml

查看BIG-IP Controller的部署进度

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[root@master01 ~]# oc get pod
NAME                                READY     STATUS    RESTARTS   AGE
f5-bigip-ctlr-01-7f44695b97-lmwdh   1/1       Running   0          17h
f5-bigip-ctlr-02-54df674f58-j2x26   1/1       Running   0          17h

当BIG-IP Controller POD启动后，在F5上会自动创建两个virtual servers

  • “ose-vserver” 为HTTP请求
  • “https-ose-vserver” 为HTTPS请求
    这两个virtual servers是Openshift下所有的Route共用的。

创建新的应用F5-Test，并创建HTTP Route Openshift

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oc new-project f5-test
oc new-app harbor.example.com/public/nginx:1.14 --name=f5-test --allow-missing-images
oc expose dc/f5-test --port=8080

创建Route

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apiVersion: route.openshift.io/v1
kind: Route
metadata:
  labels:
    name: f5-test
  name: f5-test
  annotations:
    virtual-server.f5.com/balance: least-connections-node
spec:
  host: f5-test.example.com
  port:
    targetPort: 8080
  to:
    kind: Service
    name: f5-test

本地绑定hosts

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192.168.200.80 f5-test.example.com

浏览器访问http://f5-test.example.com，即能看到应用页面。

创建HTTPS Route（仍然使用上面的应用） Openshift

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apiVersion: route.openshift.io/v1
kind: Route
metadata:
  annotations:
    virtual-server.f5.com/balance: least-connections-node
  labels:
    app: f5-test
  name: f5-test-2
spec:
  host: f5-tes-2t.example.com
  tls:
    insecureEdgeTerminationPolicy: Allow
    termination: edge
  to:
    kind: Service
    name: f5-test

本地绑定hosts

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192.168.200.80 f5-test-2.example.com

浏览器访问https://f5-test.example.com，即能看到应用页面。

说明

  • Openshit上创建Service后，F5会自动创建新的Pool，Pool里的资源即为Service下的Pod
  • 请求到达F5后，F5根据请求的域名，找到对应的Pool，请求直接到达Pod。不会请求集群里的Route。

参考资料