High Availability with Heartbeat on Unbuntu

1. make sure all server/node can comunicate
2. install heartbeat > sudo apt-get install heartbeat
3. Create ha.cf File, On both servers,
    sudo vi /etc/ha.d/ha.cf
  
  keepalive 2
  warntime 5
  deadtime 15
  initdead 90
  udpport 694
  auto_failback on
  ucast eth0 172.16.10.135 #for node2 change ip node1
  logfile /var/log/ha-log
  node eoblas05
  node eoblas03 

4. Create authkeys File

The authorization key is used to allow cluster members to join a cluster. We can simply generate a random key for this purpose.

On the primary node, run these commands to generate a suitable authorization key in an environment variable named AUTH_KEY:

if [ -z "${AUTH_KEY}" ]; then
  export AUTH_KEY="$(command dd if='/dev/urandom' bs=512 count=1 2>'/dev/null' \
      | command openssl sha1 \
      | command cut --delimiter=' ' --fields=2)"
fi

Then write the /etc/ha.d/authkeys file with these commands:

sudo bash -c "{
  echo auth1
  echo 1 sha1 $AUTH_KEY
} > /etc/ha.d/authkeys"

Check the contents of the authkeys file like this:

    sudo cat /etc/ha.d/authkeys

It should like something like this (with a different authorization key):

/etc/ha.d/authkeys example:
auth1
1 sha1 d1e6557e2fcb30ff8d4d3ae65b50345fa46a2faa

Ensure that the file is only readable by root:

    sudo chmod 600 /etc/ha.d/authkeys

Now copy the /etc/ha.d/authkeys file from your primary node to your secondary node. You can do this manually, or with scp.

On the secondary server, be sure to set the permissions of the authkeys file:

    sudo chmod 600 /etc/ha.d/authkeys

Both servers should have an identical /etc/ha.d/authkeys file.

5. Create haresources File

The haresources file specifies preferred hosts paired with services that the cluster manages. The preferred host is the node that should run the associated service(s) if the node is available. If the preferred host is not available, i.e. it is not reachable by the cluster, one of the other nodes will take over. In other words, the secondary server will take over if the primary server goes down.

On both servers, open the haresources file in your favorite editor. We'll use vi:

    sudo vi /etc/ha.d/haresources

    eoblas05 IPaddr::172.16.10.35/24 apache2
  #eoblas05 IPaddr::172.16.10.35/24 drbddisk::r0 Filesystem::/dev/drbd0::/data::ext4::noatime  mysql apache2  (contoh untuk drbd dan mysql)

6. TESTING WITH APACHE WEB SERVER

  
Please try to access an alias IP from browser. You will see a text This is node1. Please try to stop Heartbeat service on node1 and refresh browser. You will see a text This is node2 (all services handled by Heartbeat on node1 will be taken by node2). For failback, please start again Heartbeat service on node1 (all services handled by Heartbeat on node2 will be taken again by node1)