--- layout: docs page_title: Federation Between VMs and Kubernetes sidebar_title: Federation Between VMs and Kubernetes description: >- Federating Kubernetes clusters and VMs. --- # Federation Between VMs and Kubernetes -> **1.8.0+:** This feature is available in Consul versions 1.8.0 and higher ~> This topic requires familiarity with [Mesh Gateways](/docs/connect/mesh-gateway) and [WAN Federation Via Mesh Gateways](/docs/connect/gateways/wan-federation-via-mesh-gateways). Consul datacenters running on non-kubernetes platforms like VMs or bare metal can be federated with Kubernetes datacenters. Just like with Kubernetes, one datacenter must be the [primary](/docs/k8s/installation/multi-cluster/kubernetes#primary-datacenter). ## Kubernetes as the Primary If your primary datacenter is running on Kubernetes, use the Helm config from the [Primary Datacenter](/docs/k8s/installation/multi-cluster/kubernetes#primary-datacenter) section to install Consul. Once installed, you'll need to export the following information from the primary Kubernetes cluster: 1. The certificate authority cert: ```sh kubectl get secrets/consul-ca-cert --template='{{index .data "tls.crt" }}' | base64 -D > consul-agent-ca.pem ``` and the certificate authority signing key: ```sh kubectl get secrets/consul-ca-key --template='{{index .data "tls.key" }}' | base64 -D > consul-agent-ca-key.pem ``` With the `consul-agent-ca.pem` and `consul-agent-ca-key.pem` files you can create certificates for your servers and clients running on VMs that share the same certificate authority as your Kubernetes servers. You can use the `consul tls` commands to generate those certificates: ```sh # NOTE: consul-agent-ca.pem and consul-agent-ca-key.pem must be in the current # directory. $ consul tls cert create -server -dc=vm-dc ==> WARNING: Server Certificates grants authority to become a server and access all state in the cluster including root keys and all ACL tokens. Do not distribute them to production hosts that are not server nodes. Store them as securely as CA keys. ==> Using consul-agent-ca.pem and consul-agent-ca-key.pem ==> Saved vm-dc-server-consul-0.pem ==> Saved vm-dc-server-consul-0-key.pem ``` See the help for output of `consul tls cert create -h` to see more options for generating server certificates. These certificates can be used in your server config file: ```hcl # server.hcl cert_file = "vm-dc-server-consul-0.pem" key_file = "vm-dc-server-consul-0-key.pem" ca_file = "consul-agent-ca.pem" ``` For clients, you can generate TLS certs with: ```shell-session $ consul tls cert create -client ==> Using consul-agent-ca.pem and consul-agent-ca-key.pem ==> Saved dc1-client-consul-0.pem ==> Saved dc1-client-consul-0-key.pem ``` Or use the [auto_encrypt](/docs/agent/options#auto_encrypt) feature. 1. The WAN addresses of the mesh gateways: ```shell-session $ kubectl exec statefulset/consul-server -- sh -c \ 'curl -sk https://localhost:8501/v1/catalog/service/mesh-gateway | jq ".[].ServiceTaggedAddresses.wan"' { "Address": "1.2.3.4", "Port": 443 } { "Address": "1.2.3.4", "Port": 443 } ``` In this example, the addresses are the same because both mesh gateway pods are fronted by the same Kubernetes load balancer. These addresses will be used in the server config for the `primary_gateways` setting: ```hcl primary_gateways = ["1.2.3.4:443"] ``` 1. If ACLs are enabled, you'll also need the replication ACL token: ```shell-session $ kubectl get secrets/consul-acl-replication-acl-token --template='{{.data.token}}' e7924dd1-dc3f-f644-da54-81a73ba0a178 ``` This token will be used in the server config for the replication token. You must also create your own agent policy and token. ```hcl acls { tokens { agent = "" replication = "e7924dd1-dc3f-f644-da54-81a73ba0a178" } } ``` 1. If gossip encryption is enabled, you'll need the key as well. The command to retrieve the key will depend on which Kubernetes secret you've stored it in. This key will be used in server and client configs for the `encrypt` setting: ```hcl encrypt = "uF+GsbI66cuWU21kiXLze5JLEX5j4iDFlDTb0ZWNpDI=" ``` A final example server config file might look like: ```hcl # From above cert_file = "vm-dc-server-consul-0.pem" key_file = "vm-dc-server-consul-0-key.pem" ca_file = "consul-agent-ca.pem" primary_gateways = ["1.2.3.4:443"] acl { enabled = true default_policy = "deny" down_policy = "extend-cache" tokens { agent = "e7924dd1-dc3f-f644-da54-81a73ba0a178" replication = "e7924dd1-dc3f-f644-da54-81a73ba0a178" } } encrypt = "uF+GsbI66cuWU21kiXLze5JLEX5j4iDFlDTb0ZWNpDI=" # Other server settings server = true datacenter = "vm-dc" data_dir = "/opt/consul" enable_central_service_config = true primary_datacenter = "dc1" connect { enabled = true enable_mesh_gateway_wan_federation = true } verify_incoming_rpc = true verify_outgoing = true verify_server_hostname = true ports { https = 8501 http = -1 grpc = 8502 } ``` ## Kubernetes as the Secondary If you're running your primary datacenter on VMs then you'll need to manually construct the [Federation Secret](/docs/k8s/installation/multi-cluster/kubernetes#federation-secret) in order to federate Kubernetes clusters as secondaries. -> Your VM cluster must be running mesh gateways, and have mesh gateway WAN federation enabled. See [WAN Federation via Mesh Gateways](/docs/connect/gateways/wan-federation-via-mesh-gateways). You'll need: 1. The root certificate authority cert placed in `consul-agent-ca.pem`. 1. The root certificate authority key placed in `consul-agent-ca-key.pem`. 1. The IP addresses of the mesh gateways running in your VM datacenter. These must be routable from the Kubernetes cluster. 1. If ACLs are enabled you must create an ACL replication token with the following rules: ```hcl acl = "write" operator = "write" agent_prefix "" { policy = "read" } node_prefix "" { policy = "write" } service_prefix "" { policy = "read" intentions = "read" } ``` This token is used for ACL replication and for automatic ACL management in Kubernetes. If you're running Consul Enterprise you'll need the rules: ```hcl acl = "write" operator = "write" agent_prefix "" { policy = "read" } node_prefix "" { policy = "write" } namespace_prefix "" { service_prefix "" { policy = "read" intentions = "read" } } ``` 1. If gossip encryption is enabled, you'll need the key. With that data ready, you can create the Kubernetes federation secret: ```sh kubectl create secret generic consul-federation \ --from-literal=caCert=$(cat consul-agent-ca.pem) \ --from-literal=caKey=$(cat consul-agent-ca-key.pem) # If ACLs are enabled uncomment. # --from-literal=replicationToken="" \ # If using gossip encryption uncomment. # --from-literal=gossipEncryptionKey="" ``` Then use the following Helm config file: ```yaml global: name: consul datacenter: dc2 tls: enabled: true caCert: secretName: consul-federation secretKey: caCert caKey: secretName: consul-federation secretKey: caKey # Delete this acls section if ACLs are disabled. acls: manageSystemACLs: true replicationToken: secretName: consul-federation secretKey: replicationToken federation: enabled: true # Delete this gossipEncryption section if gossip encryption is disabled. gossipEncryption: secretName: consul-federation secretKey: gossipEncryptionKey connectInject: enabled: true meshGateway: enabled: true server: extraConfig: | { "primary_datacenter": "", "primary_gateways": ["", "", ...] } ``` -> **NOTE: ** You must fill out the `server.extraConfig` section with the datacenter name of your primary datacenter running on VMs and with the IPs of your mesh gateways running on VMs. With your config file ready to go, follow our [Installation Guide](/docs/k8s/installation/install) to install Consul on your secondary cluster(s). ## Next Steps Read the [Verifying Federation](/docs/k8s/installation/multi-cluster/kubernetes#verifying-federation) section to verify that federation is working as expected.