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Set up Konnectivity service
The Konnectivity service provides a TCP level proxy for the control plane to cluster communication.
Before you begin
You need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. If you do not already have a cluster, you can create one by using Minikube, or you can use one of these Kubernetes playgrounds:
Configure the Konnectivity service
The following steps require an egress configuration, for example:
apiVersion: apiserver.k8s.io/v1beta1
kind: EgressSelectorConfiguration
egressSelections:
# Since we want to control the egress traffic to the cluster, we use the
# "cluster" as the name. Other supported values are "etcd", and "master".
- name: cluster
connection:
# This controls the protocol between the API Server and the Konnectivity
# server. Supported values are "GRPC" and "HTTPConnect". There is no
# end user visible difference between the two modes. You need to set the
# Konnectivity server to work in the same mode.
proxyProtocol: GRPC
transport:
# This controls what transport the API Server uses to communicate with the
# Konnectivity server. UDS is recommended if the Konnectivity server
# locates on the same machine as the API Server. You need to configure the
# Konnectivity server to listen on the same UDS socket.
# The other supported transport is "tcp". You will need to set up TLS
# config to secure the TCP transport.
uds:
udsName: /etc/srv/kubernetes/konnectivity-server/konnectivity-server.socket
You need to configure the API Server to use the Konnectivity service and direct the network traffic to the cluster nodes:
- Create an egress configuration file such as
admin/konnectivity/egress-selector-configuration.yaml
. - Set the
--egress-selector-config-file
flag of the API Server to the path of your API Server egress configuration file.
Next, you need to deploy the Konnectivity server and agents. kubernetes-sigs/apiserver-network-proxy is a reference implementation.
Deploy the Konnectivity server on your control plane node. The provided
konnectivity-server.yaml
manifest assumes
that the Kubernetes components are deployed as a static PodA pod managed directly by the kubelet daemon on a specific node. in your cluster. If not, you can deploy the Konnectivity
server as a DaemonSet.
apiVersion: v1
kind: Pod
metadata:
name: konnectivity-server
namespace: kube-system
spec:
priorityClassName: system-cluster-critical
hostNetwork: true
containers:
- name: konnectivity-server-container
image: us.gcr.io/k8s-artifacts-prod/kas-network-proxy/proxy-server:v0.0.8
command: ["/proxy-server"]
args: [
"--log-file=/var/log/konnectivity-server.log",
"--logtostderr=false",
"--log-file-max-size=0",
# This needs to be consistent with the value set in egressSelectorConfiguration.
"--uds-name=/etc/srv/kubernetes/konnectivity-server/konnectivity-server.socket",
# The following two lines assume the Konnectivity server is
# deployed on the same machine as the apiserver, and the certs and
# key of the API Server are at the specified location.
"--cluster-cert=/etc/srv/kubernetes/pki/apiserver.crt",
"--cluster-key=/etc/srv/kubernetes/pki/apiserver.key",
# This needs to be consistent with the value set in egressSelectorConfiguration.
"--mode=grpc",
"--server-port=0",
"--agent-port=8132",
"--admin-port=8133",
"--agent-namespace=kube-system",
"--agent-service-account=konnectivity-agent",
"--kubeconfig=/etc/srv/kubernetes/konnectivity-server/kubeconfig",
"--authentication-audience=system:konnectivity-server"
]
livenessProbe:
httpGet:
scheme: HTTP
host: 127.0.0.1
port: 8133
path: /healthz
initialDelaySeconds: 30
timeoutSeconds: 60
ports:
- name: agentport
containerPort: 8132
hostPort: 8132
- name: adminport
containerPort: 8133
hostPort: 8133
volumeMounts:
- name: varlogkonnectivityserver
mountPath: /var/log/konnectivity-server.log
readOnly: false
- name: pki
mountPath: /etc/srv/kubernetes/pki
readOnly: true
- name: konnectivity-uds
mountPath: /etc/srv/kubernetes/konnectivity-server
readOnly: false
volumes:
- name: varlogkonnectivityserver
hostPath:
path: /var/log/konnectivity-server.log
type: FileOrCreate
- name: pki
hostPath:
path: /etc/srv/kubernetes/pki
- name: konnectivity-uds
hostPath:
path: /etc/srv/kubernetes/konnectivity-server
type: DirectoryOrCreate
Then deploy the Konnectivity agents in your cluster:
apiVersion: apps/v1
# Alternatively, you can deploy the agents as Deployments. It is not necessary
# to have an agent on each node.
kind: DaemonSet
metadata:
labels:
addonmanager.kubernetes.io/mode: Reconcile
k8s-app: konnectivity-agent
namespace: kube-system
name: konnectivity-agent
spec:
selector:
matchLabels:
k8s-app: konnectivity-agent
template:
metadata:
labels:
k8s-app: konnectivity-agent
spec:
priorityClassName: system-cluster-critical
tolerations:
- key: "CriticalAddonsOnly"
operator: "Exists"
containers:
- image: us.gcr.io/k8s-artifacts-prod/kas-network-proxy/proxy-agent:v0.0.8
name: konnectivity-agent
command: ["/proxy-agent"]
args: [
"--logtostderr=true",
"--ca-cert=/var/run/secrets/kubernetes.io/serviceaccount/ca.crt",
# Since the konnectivity server runs with hostNetwork=true,
# this is the IP address of the master machine.
"--proxy-server-host=35.225.206.7",
"--proxy-server-port=8132",
"--service-account-token-path=/var/run/secrets/tokens/konnectivity-agent-token"
]
volumeMounts:
- mountPath: /var/run/secrets/tokens
name: konnectivity-agent-token
livenessProbe:
httpGet:
port: 8093
path: /healthz
initialDelaySeconds: 15
timeoutSeconds: 15
serviceAccountName: konnectivity-agent
volumes:
- name: konnectivity-agent-token
projected:
sources:
- serviceAccountToken:
path: konnectivity-agent-token
audience: system:konnectivity-server
Last, if RBAC is enabled in your cluster, create the relevant RBAC rules:
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
name: system:konnectivity-server
labels:
kubernetes.io/cluster-service: "true"
addonmanager.kubernetes.io/mode: Reconcile
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: system:auth-delegator
subjects:
- apiGroup: rbac.authorization.k8s.io
kind: User
name: system:konnectivity-server
---
apiVersion: v1
kind: ServiceAccount
metadata:
name: konnectivity-agent
namespace: kube-system
labels:
kubernetes.io/cluster-service: "true"
addonmanager.kubernetes.io/mode: Reconcile