How to build a 2 node cluster running apache web server on virtualbox

## create the shared disk on the virtualbox host VBoxManage createhd --filename D:\home\vm\RHELcluster\sharedisk\csd1 --size 10240 --variant Fixed --format VDI VBoxManage modifyhd D:\home\vm\RHELcluster\sharedisk\csd1.vdi --type shareable ## on both VMs, poweroff and add the shared disk as new disk on the same disk controller ## update /etc/hosts for both nodes 172.24.11.11 rhel7n1.example.com rhel7n1 172.24.11.12 rhel7n2.example.com rhel7n2 172.24.11.13 rhel7vip.example.com rhel7vip ## on both nodes, enable RHEL HA repository and install the required packages subscription-manager repos --disable=* --enable=rhel-7-server-rpms --enable=rhel-ha-for-rhel-7-server-rpms yum install -y pcs pacemaker fence-agents-all ## On both nodes, add firewall rules for HA firewall-cmd --permanent --add-service=high-availability firewall-cmd --reload ## on both nodes, set the password for the hacluster user echo "hacluster:your_password_here" | chpasswd ## on both nodes, start and enable pcsd service systemctl start pcsd systemctl enable pcsd ## on node 1, authorize the nodes ## when prompted login as hacluster user pcs cluster auth rhel7n1.example.com rhel7n2.example.com (command output) Username: hacluster Password: ********** rhel7n2.example.com: Authorized rhel7n1.example.com: Authorized ## on node 1, setup the cluster and start it immediately pcs cluster setup --start --name mycluster rhel7n1.example.com rhel7n2.example.com (command output) Destroying cluster on nodes: rhel7n1.example.com, rhel7n2.example.com... rhel7n1.example.com: Stopping Cluster (pacemaker)... rhel7n2.example.com: Stopping Cluster (pacemaker)... rhel7n1.example.com: Successfully destroyed cluster rhel7n2.example.com: Successfully destroyed cluster Sending 'pacemaker_remote authkey' to 'rhel7n1.example.com', 'rhel7n2.example.com' rhel7n1.example.com: successful distribution of the file 'pacemaker_remote authkey' rhel7n2.example.com: successful distribution of the file 'pacemaker_remote authkey' Sending cluster config files to the nodes... rhel7n1.example.com: Succeeded rhel7n2.example.com: Succeeded Starting cluster on nodes: rhel7n1.example.com, rhel7n2.example.com... rhel7n1.example.com: Starting Cluster (corosync)... rhel7n2.example.com: Starting Cluster (corosync)... rhel7n1.example.com: Starting Cluster (pacemaker)... rhel7n2.example.com: Starting Cluster (pacemaker)... Synchronizing pcsd certificates on nodes rhel7n1.example.com, rhel7n2.example.com... rhel7n2.example.com: Success rhel7n1.example.com: Success Restarting pcsd on the nodes in order to reload the certificates... rhel7n2.example.com: Success rhel7n1.example.com: Success ## On node 1, configure the cluster to enable start automatically on boot pcs cluster enable --all (command output) rhel7n1.example.com: Cluster Enabled rhel7n2.example.com: Cluster Enabled ## For nodes on virtualbox, we don't have power fencing ## on node1, disable the stonith-enabled property of the cluster pcs property set stonith-enabled=false ## on node 1, identify the shared disk and create the LVM pv, vg, lv ## e.g. /dev/sdb in our example pvcreate /dev/sdb vgcreate vg_data /dev/sdb lvcreate -n lv_data -l 100%FREE vg_data mkfs.ext4 /dev/vg_data/lv_data ## on node 2, confirm that the lv is visible in node 2, by running lsblk lsblk ## if the lv vg_data-lv_data is not visible, reboot node 2, otherwise skipreboot

## on both nodes, install the required packages for apache web server yum install -y httpd wget ## on node 1, mount the shared filesystem for apache web server mount /dev/vg_data/lv_data /var/www mkdir /var/www/html mkdir /var/www/cgi-bin mkdir /var/www/error restorecon -R /var/www ls -ldZ /var/www ## on node 1, create the default page for the apache web server cat <<EOF > /var/www/html/index.html <html> <body>This page is served by Apache Web server on RHEL High Availability Cluster</body> </html> EOF ## on both nodes, add the following config to apache, add to the end of /etc/httpd/conf/httpd.conf ## PCS Cluster config <Location /server-status> SetHandler server-status Order deny,allow Deny from all Allow from 127.0.0.1 </Location> ## on node 1, unmount /var/www umount /var/www ## on both nodes, add the firewall rules for http firewall-cmd --permanent --add-service=http firewall-cmd --reload ## on node 1, create the cluster resources pcs resource create httpd_fs Filesystem device="/dev/mapper/vg_data-lv_data" directory="/var/www" fstype="ext4" --group apache pcs resource create httpd_vip IPaddr2 ip=172.24.11.13 cidr_netmask=24 --group apache pcs resource create httpd_svc apache configfile="/etc/httpd/conf/httpd.conf" statusurl="http://127.0.0.1/server-status" --group apache ## When we use the apache resource agent to manage Apache, it does not use systemd. ## We must edit the logrotate script supplied with Apache ## so that it does not use systemctl to reload Apache ## On both nodes, Change logrotate config for apache /etc/logrotate.d/httpd as follows From: /var/log/httpd/*log { missingok notifempty sharedscripts delaycompress postrotate /bin/systemctl reload httpd.service > /dev/null 2>/dev/null || true endscript } To: /var/log/httpd/*log { missingok notifempty sharedscripts delaycompress postrotate /usr/bin/test -f /run/httpd.pid >/dev/null 2>/dev/null && /usr/bin/ps -q $(/usr/bin/cat /run/httpd.pid) >/dev/null 2>/dev/null && /usr/sbin/httpd -f /etc/httpd/conf/httpd.conf -c "PidFile /run/httpd.pid" -k graceful > /dev/null 2>/dev/null || true` endscript } ## On both nodes, Set locking_type suitable for HA LVM use lvmconf --enable-halvm --services --startstopservices ## On both nodes, list the vg vgs --noheadings -o vg_name ## on both nodes, note which VG are not for the cluster to manage ## and add to the bottom of /etc/lvm/lvm.conf ## in our case rhel is the vg name for the root filesystem, so we add to the volume_list array ## if there are more than one vg, separate with comma e.g. [ "vg1", "vg2" ] echo 'volume_list = [ "rhel" ]' >> /etc/lvm/lvm.conf ## On both nodes, rebuild the initramfs boot image to guarantee that ## the boot image will not try to activate a volume group controlled by the cluster, ## The command will take about 1 minute to complete dracut -H -f /boot/initramfs-$(uname -r).img $(uname -r) ## reboot both nodes reboot ## check pcs cluster status pcs status ## verify the web server by visiting the VIP curl http://172.24.11.13