System requirements

4 MINUTE READ

Node requirements

  • x86-64, arm64, ppc64le, or s390x processor

  • Linux kernel 3.10 or later with required dependencies. The following distributions have the required kernel, its dependencies, and are known to work well with Calico and Kubernetes.
    • RedHat Linux 7
    • CentOS 7
    • CoreOS Container Linux stable
    • Ubuntu 16.04
    • Debian 8
  • Calico must be able to manage cali* interfaces on the host. When IPIP is enabled (the default), Calico also needs to be able to manage tunl* interfaces. When VXLAN is enabled, Calico also needs to be able to manage the vxlan.calico interface.

    Note: Many Linux distributions, such as most of the above, include NetworkManager. By default, NetworkManager does not allow Calico to manage interfaces. If your nodes have NetworkManager, complete the steps in Preventing NetworkManager from controlling Calico interfaces before installing Calico.

  • If your Linux distribution comes with installed Firewalld or another iptables manager it should be disabled. These may interfere with rules added by Calico and result in unexpected behavior.

    Note: If a host firewall is needed, it can be configured by Calico HostEndpoint and GlobalNetworkPolicy. More information about configuration at Security for host.

Key/value store

Calico v3.23 requires a key/value store accessible by all Calico components. On Kubernetes, you can configure Calico to access an etcdv3 cluster directly or to use the Kubernetes API datastore.

Network requirements

Ensure that your hosts and firewalls allow the necessary traffic based on your configuration.

Configuration Host(s) Connection type Port/protocol
Calico networking (BGP) All Bidirectional TCP 179
Calico networking with IP-in-IP enabled (default) All Bidirectional IP-in-IP, often represented by its protocol number 4
Calico networking with VXLAN enabled All Bidirectional UDP 4789
Calico networking with Typha enabled Typha agent hosts Incoming TCP 5473 (default)
flannel networking (VXLAN) All Bidirectional UDP 4789
All kube-apiserver host Incoming Often TCP 443 or 6443*
etcd datastore etcd hosts Incoming Officially TCP 2379 but can vary

* The value passed to kube-apiserver using the --secure-port flag. If you cannot locate this, check the targetPort value returned by kubectl get svc kubernetes -o yaml.

Privileges

Ensure that Calico has the CAP_SYS_ADMIN privilege.

The simplest way to provide the necessary privilege is to run Calico as root or in a privileged container. When installed as a Kubernetes daemon set, Calico meets this requirement by running as a privileged container. This requires that the kubelet be allowed to run privileged containers. There are two ways this can be achieved.

Kubernetes requirements

Supported versions

We test Calico v3.23 against the following Kubernetes versions.

  • v1.21
  • v1.22
  • v1.23

Due to changes in the Kubernetes API, Calico v3.23 will not work on Kubernetes v1.15 or below. v1.16-v1.18 may work, but they are no longer tested. Newer versions may also work, but we recommend upgrading to a version of Calico that is tested against the newer Kubernetes version.

CNI plug-in enabled

Calico is installed as a CNI plugin. The kubelet must be configured to use CNI networking by passing the --network-plugin=cni argument. (On kubeadm, this is the default.)

Other network providers

Calico must be the only network provider in each cluster. We do not currently support migrating a cluster with another network provider to use Calico networking.

Supported kube-proxy modes

Calico supports the following kube-proxy modes:

IP pool configuration

The IP range selected for pod IP addresses cannot overlap with any other IP ranges in your network, including:

  • The Kubernetes service cluster IP range
  • The range from which host IPs are allocated

Application layer policy requirements

Note that Kubernetes version 1.16+ requires Istio version 1.2 or greater. Note that Istio version 1.9 requires Kubernetes version 1.17-1.20. Note that Istio version 1.10 is supported on Kubernetes version 1.18-1.21, but has been tested on Kubernetes version 1.22.

Kernel dependencies

Tip: If you are using one of the recommended distributions, you will already satisfy these.

Due to the large number of distributions and kernel version out there, it’s hard to be precise about the names of the particular kernel modules that are required to run Calico. However, in general, you’ll need:

  • The iptables modules (both the “legacy” and “nft” variants are supported). These are typically broken up into many small modules, one for each type of match criteria and one for each type of action. Calico requires:

    • The “base” modules (including the IPv6 versions if IPv6 is enabled in your cluster).
    • At least the following match criteria: set, rpfilter, addrtype, comment, conntrack, icmp, tcp, udp, ipvs, icmpv6 (if IPv6 is enabled in your kernel), mark, multiport, rpfilter, sctp, ipvs (if using kube-proxy in IPVS mode).
    • At least the following actions: REJECT, ACCEPT, DROP, LOG.
  • IP sets support.
  • Netfilter Conntrack support compiled in (with SCTP support if using SCTP).
  • IPVS support if using kube-proxy in IPVS mode.
  • IPIP, VXLAN, Wireguard support, if using Calico networking in one of those modes.
  • eBPF (including the tc hook support) and XDP (if you want to use the eBPF dataplane).