ha-nfs-vs

Prereq

apt-get install -y nfs-kernel-server drbd8-utils ntp pacemaker crmsh haveged

Configuration of DRDB

1. create volume with partition

fdisk /dev/vdb

2. add sysctl.conf parameters

# drbd tuning
net.ipv4.tcp_no_metrics_save = 1
net.core.rmem_max = 33554432
net.core.wmem_max = 33554432
net.ipv4.tcp_rmem = 4096 87380 33554432
net.ipv4.tcp_wmem = 4096 87380 33554432
vm.dirty_ratio = 10
vm.dirty_background_ratio = 4

3. edit configuration of DRDB in /etc/drdb.conf and /etc/drbd.d/*.res (see examples in this repo)

4. create drdb device

modprobe drbd
drbdadm create-md r0
drbdadm up r0
#only on one side run 
drbdadm primary test_drive --force
#monitoring sync 
watch cat /proc/drbd

5. create device and map to server

mkfs.ext4 /dev/drbd0
mount /dev/drdb0 /mnt

6. Disable drdb service because it will be managed by pacemaker

systemctl disable drbd
drbdadm down r0

Configuring corosync

1. add corosync config on both node (see examples in this repo)
2. generate key at primary node

sudo corosync-keygen

3. copy key to second node

sudo scp /etc/corosync/authkey username@server_B_ip:  /etc/corosync/
sudo chown root: /etc/corosync/authkey
sudo chmod 400 /etc/corosync/authkey

4. enable corosync

sudo mkdir -p /etc/corosync/service.d

/etc/corosync/service.d/pcmk

# add 
service {
  name: pacemaker
  ver: 1
}

/etc/default/corosync

START=yes

systemctl restart corosync
systemctl status corosync

5. Check status

sudo corosync-cmapctl | grep members

Configure pacemaker

1. Update service order because pacemaker depend on corosync

sudo update-rc.d pacemaker defaults 20 01

2. Start Pacemaker

systemctl start pacemaker

3. check status

systemctl status pacemaker

4. add pacemaker configuration

node 1: ubuntu18-nfs1
node 2: ubuntu18-nfs2
primitive drbd_nfs ocf:linbit:drbd \
	params drbd_resource=r0 \
	op monitor interval=15s
primitive fs_nfs Filesystem \
	params device="/dev/drbd0" directory="/oxus/nfs" fstype=ext4 options="noatime,nodiratime" \
	op start interval=0 timeout=60 \
	op stop interval=0 timeout=120
primitive nfs nfsserver \
	params nfs_init_script="/etc/init.d/nfs-kernel-server" nfs_shared_infodir="/oxus/nfs" nfs_ip=10.96.1.150 \
	op monitor interval=5s
primitive p_ip_nfs IPaddr2 \
	params ip=10.96.1.150 cidr_netmask=24 nic=ens3 \
	op monitor interval=30s --group HA
group HA fs_nfs p_ip_nfs nfs \
	meta target-role=Started
ms ms_drbd_nfs drbd_nfs \
	meta master-max=1 master-node-max=1 clone-max=2 clone-node-max=1 notify=true
order fs-nfs-before-nfs inf: fs_nfs:start nfs:start
order ms-drbd-nfs-before-fs-nfs inf: ms_drbd_nfs:promote fs_nfs:start
colocation ms-drbd-nfs-with-ha inf: ms_drbd_nfs:Master HA
property cib-bootstrap-options: \
	have-watchdog=false \
	dc-version=1.1.18-2b07d5c5a9 \
	cluster-infrastructure=corosync \
	cluster-name=debian \
	stonith-enabled=false \
	no-quorum-policy=ignore

links

https://www.howtoforge.com/high-availability-nfs-with-drbd-plus-heartbeat https://www.linuxtechi.com/configure-nfs-server-clustering-pacemaker-centos-7-rhel-7/ https://medium.com/@yenthanh/high-availability-using-corosync-pacemaker-on-ubuntu-16-04-bdebc6183fc5