2. Share the /dockerdata-nfs directory between Kubernetes nodes

When setting up a Kubernetes cluster, the folder /dockerdata-nfs must be shared between all of the Kubernetes worker nodes. This folder is used as a volume by the ONAP pods to share data, so there can only be one copy.

On this page we will attempt to do this by setting up an NFS server on the Kubernetes Master and then mount the shared directory on all Kubernetes worker nodes. 

These instruction where written using VMs created from a ubuntu-16.04-server-cloudimg-amd64-disk1 image.

Any user can be used to run the steps in this page, as all the commands are "sudo".

On the NFS Server VM (Kubernetes Master Node)

The actual /dockerdata-nfs folder will live on Kubernetes Master node which will also be running the NFS server to export this folder.

Set up the /dockerdata-nfs Folder

Choose one of the following to create the /dockerdata-nfs folder on this VM:

#id is ubuntu
sudo mkdir -p /dockerdata-nfs
sudo chmod 777 /dockerdata-nfs

Setup the NFS Server and Export  /dockerdata-nfs Folder

Execute the following commands as ubuntu user.

sudo apt update
sudo apt  install nfs-kernel-server

sudo vi /etc/exports
# append the following
/dockerdata-nfs *(rw,no_root_squash,no_subtree_check)

sudo service nfs-kernel-server restart

On the other VMs (Kubernetes Worker Nodes)

Mount the /dockerdata-nfs Folder

On each of the Kubernetes worker nodes, mount the /dockerdata-nfs folder. Run the followings as ubuntu user.

sudo apt update
sudo apt install nfs-common -y
sudo mkdir /dockerdata-nfs
sudo chmod 777 /dockerdata-nfs


# Option 1:
sudo mount -t nfs -o proto=tcp,port=2049 <hostname or IP address of NFS server>:/dockerdata-nfs /dockerdata-nfs
sudo vi /etc/fstab
# append the following
<hostname or IP address of NFS server>:/dockerdata-nfs /dockerdata-nfs   nfs    auto  0  0


# Option 2:
sudo vi /etc/fstab
# append the following line.
<hostname or IP address of NFS server>:/dockerdata-nfs /dockerdata-nfs   nfs    auto  0  0
# run the following line
sudo mount -a

Verify it :

Tocuh a file inside /dockerdata-nfs directory on the Kubernetes Master and check to see if the same file is found under /dockerdata-nfs on all Kubernetes worker nodes.

Unmount the share directory

Use the lazy (-l) option on Kubernetes worker nodes to force unmount the mount point.

For example,

sudo umount -l /dockerdata-nfs