K
Q

How can I configure Calico to use a custom subnet as the default?

2/10/2016

I have been able to create a Kubernetes cluster on CoreOS using Calico following this guide.

As documented in the guide, Calico creates a default subnet 192.168.0.0/16. Once the services start, I can redefine the subnet by running the following commands:

$ export ETCD_AUTHORITY=127.0.0.1:6666
$ calicoctl pool remove 192.168.0.0/16
$ calicoctl pool add 10.244.0.0/16 --nat-outgoing

All work nicely. However, I would like to automate the above using cloud-config. I've tried using a OneShot service to execute the commands but it only worked partially. The new subnet 10.244.0.0/16 was added but 192.168.0.0/16 was not removed. The error was:

calicoctl[1330]: 192.168.0.0/16 is not a configured pool.

I guess that was because the default subnet was not yet created when the pool remove command executed.

So my questions are:

  1. Is there a way to configure Calico so it uses my custom subnet as the default?
  2. If not, then is there a way to poll for Calico to initialize completely before executing pool remove on the default subnet?
-- Eng T
docker
kubernetes
project-calico

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1 Answer

4/22/2016

A bit late to the party here, but...

With recent releases of Calico this is easier to automate. The calico/node container will attempt to create the 192.168.0.0/16 pool by default. If you'd like to use a different pool you can do the following:

  1. Before running the calico/node container, create the pool you'd like to use.

  2. Start the calico/node container with NO_DEFAULT_POOLS=true environment variable. This stops the container from creating the default pool. (https://github.com/projectcalico/calico-containers/blob/master/calico_node/filesystem/startup.py#L259)

Using cloud-init / systemd, I'd do something like this:

[Service]
Environment=ETCD_AUTHORITY=$private_ipv4:2379
Environment=NO_DEFAULT_POOLS=true
ExecStartPre=/opt/bin/calicoctl pool add <your ipv4 pool> --nat-outgoing
ExecStartPre=/opt/bin/calicoctl pool add <your ipv6 pool>
ExecStart=/opt/bin/calicoctl node --ip=$private_ipv4 --detach=false
Restart=always
RestartSec=10

[Install]
WantedBy=multi-user.target
-- Casey Davenport
Source: StackOverflow