Adjust the IP count value

During an MKE installation, you can alter the number of Azure IP addresses that MKE automatically provisions for pods.

By default, MKE will provision 128 addresses, from the same Azure subnet as the hosts, for each VM in the cluster. If, however, you have manually attached additional IP addresses to the VMs (by way of an ARM Template, Azure CLI or Azure Portal) or you are deploying in to small Azure subnet (less than /16), you can use an --azure-ip-count flag at install time.

Note

Do not set the --azure-ip-count variable to a value of less than 6 if you have not manually provisioned additional IP addresses for each VM. The MKE installation needs at least 6 IP addresses to allocate to the core MKE components that run as Kubernetes pods (in addition to the VM’s private IP address).

Below are several example scenarios that require the defining of the --azure-ip-count variable.

Scenario 1: Manually provisioned addresses

If you have manually provisioned additional IP addresses for each VM and want to disable MKE from dynamically provisioning more IP addresses, you must pass --azure-ip-count 0 into the MKE installation command.

Scenario 2: Reducing the number of provisioned addresses

Pass --azure-ip-count <custom_value> into the MKE installation command to reduce the number of IP addresses dynamically allocated from 128 to a custom value due to:

  • Primary use of the Swarm Orchestrator

  • Deployment of MKE on a small Azure subnet (for example, /24)

  • Plans to run a small number of Kubernetes pods on each node

To adjust this value post-installation, refer to the instructions on how to download the MKE configuration file, change the value, and update the configuration via the API.

Note

If you reduce the value post-installation, existing VMs will not reconcile and you will need to manually edit the IP count in Azure.

Run the following command to install MKE on a manager node.

docker container run --rm -it \
  --name ucp \
  --volume /var/run/docker.sock:/var/run/docker.sock \
  mirantis/ucp:3.5.12 install \
  --host-address <ucp-ip> \
  --pod-cidr <ip-address-range> \
  --cloud-provider Azure \
  --interactive

  • The --pod-cidr option maps to the IP address range that you configured for the Azure subnet.

    Note

    The pod-cidr range must match the Azure virtual network’s subnet attached to the hosts. For example, if the Azure virtual network had the range 172.0.0.0/16 with VMs provisioned on an Azure subnet of 172.0.1.0/24, then the Pod CIDR should also be 172.0.1.0/24.

    This requirement applies only when MKE does not use the VXLAN data plane. If MKE uses the VXLAN data plane, the pod-cidr range must be different than the node IP subnet.

  • The --host-address maps to the private IP address of the master node.

  • The --azure-ip-count serves to adjust the amount of IP addresses provisioned to each VM.