Adding Calico to an Existing Kubernetes Cluster
This document describes the steps required to install Calico on an existing Kubernetes cluster.
This document explains an installation of Calico that includes Kubernetes NetworkPolicy support. Older versions of Calico include annotation-based policy support. While this is no longer recommended, the documentation for annotation-based policy can still be found in an older release
Requirements
- An existing Kubernetes cluster running Kubernetes >= v1.1. To use NetworkPolicy, Kubernetes >= v1.3.0 is required.
- The kube-proxy must be started in
iptables
proxy mode. This is the default as of Kubernetes v1.2.0. - The kube-proxy must be started without the
--masquerade-all
flag, which conflicts with Calico policy. - An
etcd
cluster accessible by all nodes in the Kubernetes cluster- Calico can share the etcd cluster used by Kubernetes, but it’s recommended that a separate cluster is set up.
About the Calico Components
There are three components of a Calico / Kubernetes integration.
- The Calico per-node docker container, calico/node
- The calico-cni network plugin binaries.
- This is the combination of two binary executables and a configuration file.
- When using Kubernetes NetworkPolicy, the Calico policy controller is also required.
The calico/node
docker container must be run on the Kubernetes master and each
Kubernetes node in your cluster, as it contains the BGP agent necessary for Calico routing to occur.
The calico-cni
plugin integrates directly with the Kubernetes kubelet
process
on each node to discover which pods have been created, and adds them to Calico networking.
The calico/kube-policy-controller
container runs as a pod on top of Kubernetes and implements
the NetworkPolicy API. This component requires Kubernetes >= 1.3.0.
Installing Calico Components
There are currently two methods of installing the Calico components.
- Manual installation
- Kubernetes-hosted installation (supported in Kubernetes >= v1.4.0)
Manual Installation
1. Run calico/node
and configure the node.
The Kubernetes master and each Kubernetes node require the calico/node
container.
Each node must also be recorded in the Calico datastore.
This can be done using the calicoctl
utility.
# Download and install `calicoctl`
wget https://github.com/projectcalico/calico-containers/releases/download/v0.23.1/calicoctl
sudo chmod +x calicoctl
# Run the calico/node container
sudo ETCD_ENDPOINTS=http://<ETCD_IP>:<ETCD_PORT> ./calicoctl node
See the calicoctl node
documentation
for more information.
Example systemd unit file (calico-node.service)
If you’re using systemd as your init system then the following service file can be used.
[Unit]
Description=calicoctl node
After=docker.service
Requires=docker.service
[Service]
User=root
Environment=ETCD_ENDPOINTS=http://<ETCD_IP>:<ETCD_PORT>
PermissionsStartOnly=true
ExecStartPre=/usr/bin/wget -N -P /opt/bin https://github.com/projectcalico/calico-containers/releases/download/v0.23.1/calicoctl
ExecStartPre=/usr/bin/chmod +x /opt/bin/calicoctl
ExecStart=/opt/bin/calicoctl node --detach=false
Restart=always
RestartSec=10
[Install]
WantedBy=multi-user.target
Replace
<ETCD_IP>:<ETCD_PORT>
with your etcd configuration.
2. Download and configure the Calico CNI plugins
The Kubernetes kubelet
calls out to the calico
and calico-ipam
plugins.
Download the binaries and make sure they’re executable
wget -N -P /opt/cni/bin https://github.com/projectcalico/calico-cni/releases/download/v1.4.4/calico
wget -N -P /opt/cni/bin https://github.com/projectcalico/calico-cni/releases/download/v1.4.4/calico-ipam
chmod +x /opt/cni/bin/calico /opt/cni/bin/calico-ipam
It’s recommended that this is done as part of job that manages the kubelet
process (see below)
The Calico CNI plugins require a standard CNI config file. The policy
section is only required when
deploying the calico/kube-policy-controller
for NetworkPolicy.
mkdir -p /etc/cni/net.d
cat >/etc/cni/net.d/10-calico.conf <<EOF
{
"name": "calico-k8s-network",
"type": "calico",
"etcd_endpoints": "http://<ETCD_IP>:<ETCD_PORT>",
"log_level": "info",
"ipam": {
"type": "calico-ipam"
},
"policy": {
"type": "k8s"
},
"kubernetes": {
"kubeconfig": "</PATH/TO/KUBECONFIG>"
}
}
EOF
Replace <ETCD_IP>:<ETCD_PORT>
with your etcd configuration.
Replace </PATH/TO/KUBECONFIG>
with your kubeconfig file. See kubernetes kubeconfig for more information about kubeconfig.
For more information on configuring the Calico CNI plugins, see the configuration guide.
3. Install standard CNI lo plugin
In addition to the CNI plugin specified by the CNI config file, Kubernetes requires the standard CNI loopback plugin.
Download the file loopback
and cp it to CNI binary dir.
wget https://github.com/containernetworking/cni/releases/download/v0.3.0/cni-v0.3.0.tgz
tar -zxvf cni-v0.3.0.tgz
sudo cp loopback /opt/cin/bin/
4. Deploy the Calico network policy controller
The calico/kube-policy-controller
implements the Kubernetes NetworkPolicy API by watching the Kubernetes API for Pod, Namespace, and
NetworkPolicy events and configuring Calico in response. It runs as a single pod managed by a ReplicaSet.
To install the policy controller:
- Download the policy controller manifest.
- Modify
<ETCD_ENDPOINTS>
to point to your etcd cluster. - Install it using
kubectl
.
$ kubectl create -f policy-controller.yaml
After a few moments, you should see the policy controller enter Running
state:
$ kubectl get pods --namespace=kube-system
NAME READY STATUS RESTARTS AGE
calico-policy-controller 2/2 Running 0 1m
Kubernetes Hosted Installation
This method of installation uses Kubernetes to install Calico. This method is only supported in Kubernetes >= v1.4.0, and is currently considered experimental.
Since this method uses Kubernetes to install Calico, you must first deploy a standard Kubernetes cluster with CNI networking enabled. There are a number of ways to do this and we won’t cover them here, but make sure that it meets the desired configuration for installing Calico.
Download the Calico self-hosted manifest, calico.yaml
.
Edit the provided ConfigMap at the top of the file in order to configure Calico for your deployment. Then install the manifests using Kubernetes.
kubectl create -f calico.yaml
You should see the Calico services start in the kube-system
Namespace.
For more information, see the Calico self-hosted documentation.
Configuring Kubernetes
Configuring the Kubelet
The Kubelet needs to be configured to use the Calico network plugin when starting pods.
The kubelet
can be configured to use Calico by starting it with the following options
--network-plugin=cni
--network-plugin-dir=/etc/cni/net.d
See the kubelet
documentation
for more details.
Example systemd unit file (kubelet.service)
[Unit]
Description=Kubernetes Kubelet
Documentation=https://github.com/kubernetes/kubernetes
After=calico-node.service
Requires=calico-node.service
[Service]
ExecStartPre=/usr/bin/wget -N -P /opt/bin https://storage.googleapis.com/kubernetes-release/release/v1.4.0/bin/linux/amd64/kubelet
ExecStartPre=/usr/bin/chmod +x /opt/bin/kubelet
ExecStartPre=/usr/bin/wget -N -P /opt/cni/bin https://github.com/projectcalico/calico-cni/releases/download/v1.4.1/calico
ExecStartPre=/usr/bin/chmod +x /opt/cni/bin/calico
ExecStartPre=/usr/bin/wget -N -P /opt/cni/bin https://github.com/projectcalico/calico-cni/releases/download/v1.4.1/calico-ipam
ExecStartPre=/usr/bin/chmod +x /opt/cni/bin/calico-ipam
ExecStart=/opt/bin/kubelet \
--address=0.0.0.0 \
--allow-privileged=true \
--cluster-dns=10.100.0.10 \
--cluster-domain=cluster.local \
--config=/etc/kubernetes/manifests \
--hostname-override=$private_ipv4 \
--api-servers=http://<API SERVER IP>:8080 \
--network-plugin-dir=/etc/cni/net.d \
--network-plugin=cni \
--logtostderr=true \
--kubeconfig=/etc/kubernetes/kubelet.conf
Restart=always
RestartSec=10
[Install]
WantedBy=multi-user.target
This unit file ensures that the kubelet
binary and the calico
plugin are present.
Configuring the Kube-Proxy
In order to use Calico policy with Kubernetes, the kube-proxy
component must
be configured to leave the source address of service bound traffic intact.
This feature is first officially supported in Kubernetes v1.1.0 and is the default mode starting
in Kubernetes v1.2.0.
We highly recommend using the latest stable Kubernetes release, but if you’re using an older release there are two ways to enable this behavior.
- Option 1: Start the
kube-proxy
with the--proxy-mode=iptables
option. - Option 2: Annotate the Kubernetes Node API object with
net.experimental.kubernetes.io/proxy-mode
set toiptables
.
See the kube-proxy documentation for more details.