This module is responsible for providing a network between multiple nodes in a cluster using the cilium module.
Limitations
- Service types
NodePort
andLoadBalancer
do not work with hostNetwork endpoints in theDSR
LB mode. Switch toSNAT
if it is required. HostPort
Pods will bind only to one interface IP. If there are multiple interfaces/IPs present, Cilium will select only one of them, preferring private IP space.- Kernel requirements.
- The
cni-cilium
module requires a Linux kernel version >=5.7
. - For the
cni-cilium
module to work together with the istio, openvpn or node-local-dns module, a Linux kernel version >=5.7
is required.
- The
- OS compatibility issues:
- Ubuntu:
- not working on 18.04
- to work on 20.04 you need to install HWE kernel
- CentOS:
- 7 (needs new kernel from repository)
- 8 (needs new kernel from repository)
- Ubuntu:
A note about CiliumClusterwideNetworkPolicies
- Make sure that you deploy initial set of CiliumClusterwideNetworkPolicies with
policyAuditMode
configuration options set totrue
. Otherwise you are degrading cluster operation or even completely losing SSH connectivity to all Kubernetes Nodes. You can remove the option once allCiliumClusterwideNetworkPolicy
objects are applied and you’ve verified their effect in the Hubble UI. -
Make sure to deploy the following rule, otherwise control-plane will fail for up to 1 minute on
cilium-agent
restart. This happens due to conntrack table reset. Referencingkube-apiserver
entity helps us to “circumvent” the bug.apiVersion: "cilium.io/v2" kind: CiliumClusterwideNetworkPolicy metadata: name: "allow-control-plane-connectivity" spec: ingress: - fromEntities: - kube-apiserver nodeSelector: matchLabels: node-role.kubernetes.io/control-plane: ""
A note about Cilium work mode change
If you change the Cilium operating mode (the tunnelMode parameter) from Disabled
to VXLAN
or vice versa, you must restart all nodes, otherwise there may be problems with the availability of Pods.
A note about disabling the kube-proxy module
Cilium has the same functionality as the kube-proxy
module, so the latter is automatically disabled when the cni-cilium
module is enabled.
A note about fault-tolerant Egress Gateway
Feature is only available in Enterprise Edition
Basic mode
Using pre-configured public IPs of egress-gateway nodes.
Virtual IP mode
Allows you to dynamically assign additional IP addresses to nodes.