Standard Installation Guide¶

Privileged Mode¶

This requirement is typically met automatically by Kubernetes installers but we list it here for completeness. Kubernetes must allow to run privileged containers. In the past, this was achieved by passing the flag --allow-privileged to kubelet. The flag has since been deprecated and is being replaced by [PodSecurity policies](https://kubernetes.io/docs/concepts/policy/pod-security-policy/).

Enable CNI in Kubernetes (Required)¶

CNI - Container Network Interface is the plugin layer used by Kubernetes to delegate networking configuration. CNI must be enabled in your Kubernetes cluster in order to install Cilium. This is done by passing --network-plugin=cni to kubelet on all nodes. For more information, see the Kubernets CNI network-plugins documentation.

Mounting the BPF FS¶

This step is optional but recommended. It allows the cilium-agent to pin BPF resources to a persistent filesystem and make them persistent across restarts of the agent. If the BPF filesystem is not mounted in the host filesystem, Cilium will automatically mount the filesystem but it will be unmounted and re-mounted when the Cilium pod is restarted. This in turn will cause BPF resources to be re-created which will cause network connectivity to be disrupted. Mounting the BPF filesystem in the host mount namespace will ensure that the agent can be restarted without affecting connectivity of any pods.

In order to mount the BPF filesystem, the following command must be run in the host mount namespace. The command must only be run once during the boot process of the machine.

mount bpffs /sys/fs/bpf -t bpf

A portable way to achieve this with persistence is to add the following line to /etc/fstab and then run mount /sys/fs/bpf. This will cause the filesystem to be automatically mounted when the node boots.

bpffs                      /sys/fs/bpf             bpf     defaults 0 0

If you are using systemd to manage the kubelet, see the section Mounting BPFFS with systemd.

Enable automatic node CIDR allocation (Recommended)¶

Kubernetes has the capability to automatically allocate and assign per node IP allocation CIDR. Cilium automatically uses this feature if enabled. This is the easiest method to handle IP allocation in a Kubernetes cluster. To enable this feature, simply add the following flag when starting kube-controller-manager:

--allocate-node-cidrs

This option is not required but highly recommended.

Configuring etcd (Required)¶

After downloading the cilium.yaml file, open it with your text editor and change the ConfigMap based on the following instructions.

First, make sure the etcd-config endpoints have the correct addresses of your etcd nodes.

If you are running more than one node simply specify the complete of endpoints. The list of endpoints can accept both domain names or IP addresses. Make sure you specify the correct port used in your etcd node.

If etcd is running with TLS, there are a couple of changes that you need to do.

1. Make sure you have https in all endpoints;

2. Uncomment the line #ca-file: '/var/lib/etcd-secrets/etcd-ca' so that the certificate authority of the servers are known to Cilium;

3. Create a kubernetes secret with certificate authority file in kubernetes;

   1. Use certificate authority file, with the name ca.crt, used to create in etcd;

   2. Create the secret by executing:

      $ kubectl create secret generic -n kube-system cilium-etcd-secrets \
          --from-file=etcd-ca=ca.crt
      

If etcd is running with client to server authentication, you need make more changes to the ConfigMap:

1. Uncomment both lines #key-file: '/var/lib/etcd-secrets/etcd-client-key' and #cert-file: '/var/lib/etcd-secrets/etcd-client-crt';

2. Create a kubernetes secret with client.key and client.crt files in kubernetes.

   1. Use the file with the name client.key that contains the client key;

   2. Use the file with the name client.crt that contains the client certificate;

   3. Create the secret by executing:

      $ kubectl create secret generic -n kube-system cilium-etcd-secrets \
          --from-file=etcd-ca=ca.crt \
          --from-file=etcd-client-key=client.key \
          --from-file=etcd-client-crt=client.crt
      

Regarding the etcd configuration that is all you need to change in the ConfigMap.

Adjusting Options (Optional)¶

In the ConfigMap there are a couple of options that can be changed accordingly with your changes.

• debug - Sets to run Cilium in full debug mode, it can be changed at runtime;
• disable-ipv4 - Disables IPv4 in Cilium and endpoints managed by Cilium;
• clean-cilium-state - Removes any Cilium state, e.g. BPF policy maps, before starting the Cilium agent;
• legacy-host-allows-world - If true, the policy with the entity reserved:host allows traffic from world. If false, the policy needs to explicitly have the entity reserved:world to allow traffic from world. It is recommended to set it to false. This option provides compatibility with Cilium 1.0 which was not able to differentiate between NodePort traffic and traffic from the host.

Any changes that you perform in the Cilium ConfigMap and in cilium-etcd-secrets Secret will require you to restart any existing Cilium pods in order for them to pick the latest configuration.

The following ConfigMap is an example where the etcd cluster is running in 2 nodes, node-1 and node-2 with TLS, and client to server authentication enabled.

apiVersion: v1
kind: ConfigMap
metadata:
  name: cilium-config
  namespace: kube-system
data:
    endpoints:
    - https://node-1:31079
    - https://node-2:31079
    #
    # In case you want to use TLS in etcd, uncomment the 'ca-file' line
    # and create a kubernetes secret by following the tutorial in
    # https://cilium.link/etcd-config
    ca-file: '/var/lib/etcd-secrets/etcd-ca'
    #
    # In case you want client to server authentication, uncomment the following
    # lines and create a kubernetes secret by following the tutorial in
    # https://cilium.link/etcd-config
    key-file: '/var/lib/etcd-secrets/etcd-client-key'
    cert-file: '/var/lib/etcd-secrets/etcd-client-crt'

  # If you want to run cilium in debug mode change this value to true
  debug: "false"
  disable-ipv4: "false"
  # If you want to clean cilium state; change this value to true
  clean-cilium-state: "false"
  legacy-host-allows-world: "false"

CNI Details¶

CNI - Container Network Interface is the plugin layer used by Kubernetes to delegate networking configuration. You can find additional information on the CNI project website.

CNI configuration is automatically being taken care of when deploying Cilium via the provided DaemonSet. The script cni-install.sh is automatically run via the postStart mechanism when the cilium pod is started.

The CNI auto installation is performed as follows:

1. The /etc/cni/net.d and /opt/cni/bin directories are mounted from the host filesystem into the pod where Cilium is running.
2. The file /etc/cni/net.d/05-cilium.conf is written in case it does not exist yet.
3. The binary cilium-cni is installed to /opt/cni/bin. Any existing binary with the name cilium-cni is overwritten.

Manually installing CNI¶

This step is typically already included in all Kubernetes distributions or Kubernetes installers but can be performed manually:

sudo mkdir -p /opt/cni
wget https://storage.googleapis.com/kubernetes-release/network-plugins/cni-0799f5732f2a11b329d9e3d51b9c8f2e3759f2ff.tar.gz
sudo tar -xvf cni-0799f5732f2a11b329d9e3d51b9c8f2e3759f2ff.tar.gz -C /opt/cni
rm cni-0799f5732f2a11b329d9e3d51b9c8f2e3759f2ff.tar.gz

Adjusting CNI configuration¶

The CNI installation can be configured with environment variables. These environment variables can be specified in the DaemonSet file like this:

env:
  - name: "CNI_CONF_NAME"
    value: "05-cilium.conf"

The following variables are supported:

If you want to further adjust the CNI configuration you may do so by creating the CNI configuration /etc/cni/net.d/05-cilium.conf manually:

sudo mkdir -p /etc/cni/net.d
sudo sh -c 'echo "{
    "name": "cilium",
    "type": "cilium-cni"
}
" > /etc/cni/net.d/05-cilium.conf'

Cilium will use any existing /etc/cni/net.d/05-cilium.conf file if it already exists on a worker node and only creates it if it does not exist yet.

Enabling hostPort Support via CNI configuration¶

Some users may want to enable hostPort. Currently, cilium does not natively support hostPort. However, users can utilize hostPort via a CNI plugin chain, by putting it in their cni-conf-dir (default /etc/cni/net.d), e.g.:

{
    "cniVersion": "0.3.1",
    "name": "cilium-portmap",
    "plugins": [
            {
                    "type": "cilium-cni"
            },
            {
                    "type": "portmap",
                    "capabilities": { "portMappings": true }
            }
    ]
}

For more information about hostPort, check the Kubernetes hostPort-CNI plugin documentation.

Running Kubernetes with CRD Validation (Recommended)¶

Custom Resource Validation was introduced in Kubernetes since version 1.8.0. This is still considered an alpha feature in Kubernetes 1.8.0 and beta in Kubernetes 1.9.0.

Since Cilium v1.0.0-rc3, Cilium will create, or update in case it exists, the Cilium Network Policy (CNP) Resource Definition with the embedded validation schema. This allows the validation of CiliumNetworkPolicy to be done on the kube-apiserver when the policy is imported with an ability to provide direct feedback when importing the resource.

To enable this feature, the flag --feature-gates=CustomResourceValidation=true must be set when starting kube-apiserver. Cilium itself will automatically make use of this feature and no additional flag is required.

To verify that the CNP resource definition contains the validation schema, run the following command:

kubectl get crd ciliumnetworkpolicies.cilium.io -o json

kubectl get crd ciliumnetworkpolicies.cilium.io -o json | grep -A 12 openAPIV3Schema
    "openAPIV3Schema": {
        "oneOf": [
            {
                "required": [
                    "spec"
                ]
            },
            {
                "required": [
                    "specs"
                ]
            }
        ],

In case the user writes a policy that does not conform to the schema, Kubernetes will return an error, e.g.:

cat <<EOF > ./bad-cnp.yaml
apiVersion: "cilium.io/v2"
kind: CiliumNetworkPolicy
description: "Policy to test multiple rules in a single file"
metadata:
  name: my-new-cilium-object
spec:
  endpointSelector:
    matchLabels:
      app: details
      track: stable
      version: v1
  ingress:
  - fromEndpoints:
    - matchLabels:
        app: reviews
        track: stable
        version: v1
    toPorts:
    - ports:
      - port: '65536'
        protocol: TCP
      rules:
        http:
        - method: GET
          path: "/health"
EOF

kubectl create -f ./bad-cnp.yaml
...
spec.ingress.toPorts.ports.port in body should match '^(6553[0-5]|655[0-2][0-9]|65[0-4][0-9]{2}|6[0-4][0-9]{3}|[1-5][0-9]{4}|[0-9]{1,4})$'

In this case, the policy has a port out of the 0-65535 range.

Mounting BPFFS with systemd¶

Due to how systemd mounts filesystems, the mount point path must be reflected in the unit filename.

cat <<EOF | sudo tee /etc/systemd/system/sys-fs-bpf.mount
[Unit]
Description=Cilium BPF mounts
Documentation=http://docs.cilium.io/
DefaultDependencies=no
Before=local-fs.target umount.target
After=swap.target

[Mount]
What=bpffs
Where=/sys/fs/bpf
Type=bpf

[Install]
WantedBy=multi-user.target
EOF

Deploying to selected nodes¶

To deploy Cilium only to a selected list of worker nodes, you can add a NodeSelector to the cilium.yaml file like this:

spec:
  template:
    spec:
      nodeSelector:
        with-network-plugin: cilium

And then label each node where Cilium should be deployed:

kubectl label node worker0 with-network-plugin=cilium
kubectl label node worker1 with-network-plugin=cilium
kubectl label node worker2 with-network-plugin=cilium