Kubealived

A Docker image and Kubernetes manifests for providing Kubernetes cluster API high availability with use of Keepalived. The solution assigns a Kubernetes master node a specified IP address, and if the node is down the address automatically moves to another master node.

Usage

A Keepalived process should run on all the master nodes of a Kubernetes cluster thefore DaemonSet is used. Keepalived assigns a specified IP address to a specified network interface. It also requires a password for internal usage, you less likely to type it anywhere, so could be random.

To avoid conflicts between several Kubealived installations within the same network the VRID (Virtual Router ID) should be different for each installation within a particular network. It should be in the range from 1 to 255.

The provided Kubealived Manifest defines placeholders for these values. They should be replaced with actual values prior to deployment:

$ IFACE="<Network Interface>"
$ IP="<IP Address>"
$ curl https://raw.githubusercontent.com/openvnf/kubealived/master/manifests/kubealived.yaml | \
       sed -e "s/_VRID_/$((1 + RANDOM % 255))/" \
           -e "s/_IFACE_/${IFACE}/" \
           -e "s/_IP_/${IP}/" \
           -e "s~_PASSWORD_~$(openssl rand -base64 8)~" | \
       kubectl create -f-

After deployment one of the master nodes should get the specified IP address on the specified network interface. If this master node or a running pod on it is down, the IP address moves to another master node.

Try With Docker

To try the image with Docker only, prepare Keepalived configuration file:

# keepalived.conf
vrrp_instance VI_1 {
    state MASTER
    interface eth0 # replace with actual network interface
    virtual_router_id 1 # (1..255) replace with another if exists in the network
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass DJCcWWJARj4= # can be generated with "openssl rand -base64 8"
    }
    virtual_ipaddress {
        10.9.8.10 # replace with needed IP address
    }
}

Run container:

$ docker run --name=kubealived --rm -d --cap-add=NET_ADMIN --net=host \
             -v $PWD/keepalived.conf:/etc/keepalived/keepalived.conf \
             quay.io/openvnf/kubealived -nl

Your host should now have the specified IP address assigned to the specified network interface. If you run the same on another host in the same network and stop this one, the IP address will be moved there.

Stop container:

$ docker stop kubealived

License

Copyright 2018-2019 Travelping GmbH

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.