calico

Kubernetes中的网络解析——以calico为例

概念

Calico 创建和管理一个扁平的三层网络(不需要overlay)，每个容器会分配一个可路由的ip。由于通信时不需要解包和封包，网络性能损耗小，易于排查，且易于水平扩展。

小规模部署时可以通过bgp client直接互联，大规模下可通过指定的BGP route reflector来完成，这样保证所有的数据流量都是通过IP路由的方式完成互联的。 Calico基于iptables还提供了丰富而灵活的网络Policy，保证通过各个节点上的ACLs来提供Workload的多租户隔离、安全组以及其他可达性限制等功能。

Calico架构

图片 - CRI架构-图片来自https://www.jianshu.com/p/f0177b84de66

calico主要由Felix,etcd,BGP client,BGP Route Reflector组成。

• Etcd：负责存储网络信息

• BGP client：负责将Felix配置的路由信息分发到其他节点

• Felix：Calico Agent，每个节点都需要运行，主要负责配置路由、配置ACLs、报告状态

• BGP Route Reflector：大规模部署时需要用到，作为BGP client的中心连接点，可以避免每个节点互联

部署

mkdir /etc/cni/net.d/

kubectl apply -f https://docs.projectcalico.org/v3.0/getting-started/kubernetes/installation/rbac.yaml

wget https://docs.projectcalico.org/v3.0/getting-started/kubernetes/installation/hosted/calico.yaml

修改etcd_endpoints的值和默认的192.168.0.0/16(不能和已有网段冲突)

kubectl apply -f calico.yaml

wget  https://github.com/projectcalico/calicoctl/releases/download/v2.0.0/calicoctl

mv calicoctl /usr/loca/bin && chmod +x /usr/local/bin/calicoctl

calicoctl get ippool

calicoctl get node

• 部署
• calicoctl命令
• 架构

yaml文件

# Calico Version v3.0.3
# https://docs.projectcalico.org/v3.0/releases#v3.0.3
# This manifest includes the following component versions:
#   calico/node:v3.0.3
#   calico/cni:v2.0.1
#   calico/kube-controllers:v2.0.1

# This ConfigMap is used to configure a self-hosted Calico installation.
kind: ConfigMap
apiVersion: v1
metadata:
  name: calico-config
  namespace: kube-system
data:
  # Configure this with the location of your etcd cluster.
  etcd_endpoints: "{{ ETCD_ENDPOINTS }}"

  # Configure the Calico backend to use.
  calico_backend: "bird"

  # The CNI network configuration to install on each node.
  cni_network_config: |-
    {
      "name": "k8s-pod-network",
      "cniVersion": "0.3.0",
      "plugins": [
        {
            "type": "calico",
            "etcd_endpoints": "__ETCD_ENDPOINTS__",
            "etcd_key_file": "__ETCD_KEY_FILE__",
            "etcd_cert_file": "__ETCD_CERT_FILE__",
            "etcd_ca_cert_file": "__ETCD_CA_CERT_FILE__",
            "log_level": "info",
            "mtu": 1500,
            "ipam": {
                "type": "calico-ipam"
            },
            "policy": {
                "type": "k8s",
                "k8s_api_root": "https://__KUBERNETES_SERVICE_HOST__:__KUBERNETES_SERVICE_PORT__",
                "k8s_auth_token": "__SERVICEACCOUNT_TOKEN__"
            },
            "kubernetes": {
                "kubeconfig": "__KUBECONFIG_FILEPATH__"
            }
        },
        {
          "type": "portmap",
          "snat": true,
          "capabilities": {"portMappings": true}
        }
      ]
    }

  # If you're using TLS enabled etcd uncomment the following.
  # You must also populate the Secret below with these files.
  etcd_ca: "/calico-secrets/etcd-ca"
  etcd_cert: "/calico-secrets/etcd-cert"
  etcd_key: "/calico-secrets/etcd-key"

---

# The following contains k8s Secrets for use with a TLS enabled etcd cluster.
# For information on populating Secrets, see http://kubernetes.io/docs/user-guide/secrets/
apiVersion: v1
kind: Secret
type: Opaque
metadata:
  name: calico-etcd-secrets
  namespace: kube-system
data:
  # Populate the following files with etcd TLS configuration if desired, but leave blank if
  # not using TLS for etcd.
  # This self-hosted install expects three files with the following names.  The values
  # should be base64 encoded strings of the entire contents of each file.
  etcd-key: "{{ calico_etcd_key }}"
  etcd-cert: "{{ calico_etcd_cert }}"
  etcd-ca: "{{ calico_etcd_ca }}"

---

# This manifest installs the calico/node container, as well
# as the Calico CNI plugins and network config on
# each master and worker node in a Kubernetes cluster.
kind: DaemonSet
apiVersion: extensions/v1beta1
metadata:
  name: calico-node
  namespace: kube-system
  labels:
    k8s-app: calico-node
spec:
  selector:
    matchLabels:
      k8s-app: calico-node
  updateStrategy:
    type: RollingUpdate
    rollingUpdate:
      maxUnavailable: 1
  template:
    metadata:
      labels:
        k8s-app: calico-node
      annotations:
        scheduler.alpha.kubernetes.io/critical-pod: ''
        scheduler.alpha.kubernetes.io/tolerations: |
          [{"key": "dedicated", "value": "master", "effect": "NoSchedule" },
           {"key":"CriticalAddonsOnly", "operator":"Exists"}]
    spec:
      hostNetwork: true
      serviceAccountName: calico-node
      # Minimize downtime during a rolling upgrade or deletion; tell Kubernetes to do a "force
      # deletion": https://kubernetes.io/docs/concepts/workloads/pods/pod/#termination-of-pods.
      terminationGracePeriodSeconds: 0
      containers:
        # Runs calico/node container on each Kubernetes node.  This
        # container programs network policy and routes on each
        # host.
        - name: calico-node
          image: "{{ CALICO_NODE_IMAGE }}"
          env:
            # The location of the Calico etcd cluster.
            - name: ETCD_ENDPOINTS
              valueFrom:
                configMapKeyRef:
                  name: calico-config
                  key: etcd_endpoints
            # Choose the backend to use.
            - name: CALICO_NETWORKING_BACKEND
              valueFrom:
                configMapKeyRef:
                  name: calico-config
                  key: calico_backend
            # Cluster type to identify the deployment type
            - name: CLUSTER_TYPE
              value: "k8s,bgp"
            # Disable file logging so `kubectl logs` works.
            - name: CALICO_DISABLE_FILE_LOGGING
              value: "true"
            # Set noderef for node controller.
            - name: CALICO_K8S_NODE_REF
              valueFrom:
                fieldRef:
                  fieldPath: spec.nodeName
            # Set Felix endpoint to host default action to ACCEPT.
            - name: FELIX_DEFAULTENDPOINTTOHOSTACTION
              value: "ACCEPT"
            # The default IPv4 pool to create on startup if none exists. Pod IPs will be
            # chosen from this range. Changing this value after installation will have
            # no effect. This should fall within `--cluster-cidr`.
            - name: CALICO_IPV4POOL_CIDR
              value: "{{ CLUSTER_CIDR }}"
            - name: CALICO_IPV4POOL_IPIP
              value: "Always"
            # Disable IPv6 on Kubernetes.
            - name: FELIX_IPV6SUPPORT
              value: "false"
            # Set Felix logging to "info"
            - name: FELIX_LOGSEVERITYSCREEN
              value: "info"
            # Set MTU for tunnel device used if ipip is enabled
            - name: FELIX_IPINIPMTU
              value: "1440"
            # Location of the CA certificate for etcd.
            - name: ETCD_CA_CERT_FILE
              valueFrom:
                configMapKeyRef:
                  name: calico-config
                  key: etcd_ca
            # Location of the client key for etcd.
            - name: ETCD_KEY_FILE
              valueFrom:
                configMapKeyRef:
                  name: calico-config
                  key: etcd_key
            # Location of the client certificate for etcd.
            - name: ETCD_CERT_FILE
              valueFrom:
                configMapKeyRef:
                  name: calico-config
                  key: etcd_cert
            # Auto-detect the BGP IP address.
            - name: IP
              value: "autodetect"
            - name: FELIX_HEALTHENABLED
              value: "true"
          securityContext:
            privileged: true
          resources:
            requests:
              cpu: 250m
          livenessProbe:
            httpGet:
              path: /liveness
              port: 9099
            periodSeconds: 10
            initialDelaySeconds: 10
            failureThreshold: 6
          readinessProbe:
            httpGet:
              path: /readiness
              port: 9099
            periodSeconds: 10
          volumeMounts:
            - mountPath: /lib/modules
              name: lib-modules
              readOnly: true
            - mountPath: /var/run/calico
              name: var-run-calico
              readOnly: false
            - mountPath: /calico-secrets
              name: etcd-certs
        # This container installs the Calico CNI binaries
        # and CNI network config file on each node.
        - name: install-cni
          image: {{ CALICO_CNI_IMAGE }}
          command: ["/install-cni.sh"]
          env:
            # Name of the CNI config file to create.
            - name: CNI_CONF_NAME
              value: "10-calico.conflist"
            # The location of the Calico etcd cluster.
            - name: ETCD_ENDPOINTS
              valueFrom:
                configMapKeyRef:
                  name: calico-config
                  key: etcd_endpoints
            # The CNI network config to install on each node.
            - name: CNI_NETWORK_CONFIG
              valueFrom:
                configMapKeyRef:
                  name: calico-config
                  key: cni_network_config
          volumeMounts:
            - mountPath: /host/opt/cni/bin
              name: cni-bin-dir
            - mountPath: /host/etc/cni/net.d
              name: cni-net-dir
            - mountPath: /calico-secrets
              name: etcd-certs
      volumes:
        # Used by calico/node.
        - name: lib-modules
          hostPath:
            path: /lib/modules
        - name: var-run-calico
          hostPath:
            path: /var/run/calico
        # Used to install CNI.
        - name: cni-bin-dir
          hostPath:
            path: /opt/cni/bin
        - name: cni-net-dir
          hostPath:
            path: /etc/cni/net.d
        # Mount in the etcd TLS secrets.
        - name: etcd-certs
          secret:
            secretName: calico-etcd-secrets

---

# This manifest deploys the Calico Kubernetes controllers.
# See https://github.com/projectcalico/kube-controllers
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: calico-kube-controllers
  namespace: kube-system
  labels:
    k8s-app: calico-kube-controllers
  annotations:
    scheduler.alpha.kubernetes.io/critical-pod: ''
    scheduler.alpha.kubernetes.io/tolerations: |
      [{"key": "dedicated", "value": "master", "effect": "NoSchedule" },
       {"key":"CriticalAddonsOnly", "operator":"Exists"}]
spec:
  # The controllers can only have a single active instance.
  replicas: 1
  strategy:
    type: Recreate
  template:
    metadata:
      name: calico-kube-controllers
      namespace: kube-system
      labels:
        k8s-app: calico-kube-controllers
    spec:
      # The controllers must run in the host network namespace so that
      # it isn't governed by policy that would prevent it from working.
      hostNetwork: true
      serviceAccountName: calico-kube-controllers
      containers:
        - name: calico-kube-controllers
          image: {{ CALICO_POLICY_IMAGE }}
          env:
            # The location of the Calico etcd cluster.
            - name: ETCD_ENDPOINTS
              valueFrom:
                configMapKeyRef:
                  name: calico-config
                  key: etcd_endpoints
            # Location of the CA certificate for etcd.
            - name: ETCD_CA_CERT_FILE
              valueFrom:
                configMapKeyRef:
                  name: calico-config
                  key: etcd_ca
            # Location of the client key for etcd.
            - name: ETCD_KEY_FILE
              valueFrom:
                configMapKeyRef:
                  name: calico-config
                  key: etcd_key
            # Location of the client certificate for etcd.
            - name: ETCD_CERT_FILE
              valueFrom:
                configMapKeyRef:
                  name: calico-config
                  key: etcd_cert
            # Choose which controllers to run.
            - name: ENABLED_CONTROLLERS
              value: policy,profile,workloadendpoint,node
          volumeMounts:
            # Mount in the etcd TLS secrets.
            - mountPath: /calico-secrets
              name: etcd-certs
      volumes:
        # Mount in the etcd TLS secrets.
        - name: etcd-certs
          secret:
            secretName: calico-etcd-secrets

---

apiVersion: v1
kind: ServiceAccount
metadata:
  name: calico-kube-controllers
  namespace: kube-system

---

apiVersion: v1
kind: ServiceAccount
metadata:
  name: calico-node
  namespace: kube-system