Differences between revisions 5 and 46 (spanning 41 versions)

Corosync and HA-proxy

We will use corosync to create a virtual IP-address which is shared by two systems. One of the systems has the virtual IP-address. If the system goes down, the other system will take over the virtual IP-address. HA-proxy will be running on each of the hosts relaying incoming HTTP-requests to two webservers.

192.168.1.49 www (virtual IP-address)
192.168.1.50 haproxy01
192.168.1.51 haproxy02

Software

apt-get install corosync haproxy crmsh

Configuration

Before binding to the DNS name www make sure the DNS server knows that name. There is no physical or virtual network interfaces, so the DNS updates has to be done manually.

Corosync

Encryption

Edit /etc/corosync/corosync.conf and make the following changes.

totem {
        crypto_cipher: aes256
        crypto_hash: sha512
}

Authentication Key

Generate the authkey. Note that this requires entropy, so use your system and the entropy will be generated. Speed this up by running dd if=/dev/vda of=/dev/null in another terminal.

corosync-keygen

Network

Add the local network and a multicast address to /etc/corosync/corosync.conf in the interface section.

interface {
        bindnetaddr: 192.168.1.0 
        mcastaddr: 239.192.1.1
}

Copy the configuration /etc/corosync/corosync.conf and the authkey /etc/corosync/authkey to the other host.

Restart corosync on both hosts to load the new configuration.

service corosync restart

HA-proxy

HA-proxy resource script

Download the HA-proxy resource script, place it in /usr/lib/ocf/resource.d/heartbeat/haproxy and make it executeable.

wget https://raw.githubusercontent.com/thisismitch/cluster-agents/master/haproxy -O /usr/lib/ocf/resource.d/heartbeat/haproxy
chmod +x /usr/lib/ocf/resource.d/heartbeat/haproxy

This has to be done on both hosts.

Webfarm

Add the following to /etc/haproxy/haproxy.cfg

listen webfarm 
        bind www:80
        mode http
        balance roundrobin
        cookie LBN insert indirect nocache
        option httpclose
        option forwardfor
        server haproxy01 www01:80 cookie node1 check
        server haproxy02 www02:80 cookie node2 check

Copy the configuration /etc/haproxy/haproxy.cfg to the other host.

Restart HA-proxy on both hosts to load the new configuration.

service haproxy restart

Nodes

Do not kill the other node.

crm configure property stonith-enabled=false

Disable quorum due to two nodes only.

crm configure property no-quorum-policy=ignore

Configure shared IP-address.

crm configure primitive haproxy_wwwSharedIP ocf:heartbeat:IPaddr2 params ip=192.168.1.49 cidr_netmask=24 op monitor interval=5s

Create heartbeat for haproxy.

crm configure primitive haproxy_wwwLoadBalance ocf:heartbeat:haproxy params conffile=/etc/haproxy/haproxy.cfg op monitor interval=10s

Make sure the same server has both IP and service at the same time.

crm configure group haproxy_www haproxy_wwwSharedIP haproxy_wwwLoadBalance

Create the relation between IP-address and haproxy servers.

currently gives: root@haproxy01:/etc/corosync# crm configure colocation haproxyWithIPs INFINITY: haproxy_wwwLoadBalance haproxy_wwwSharedIP

WARNING: haproxyWithIPs: resource haproxy_wwwLoadBalance is grouped, constraints should apply to the group

WARNING: haproxyWithIPs: resource haproxy_wwwSharedIP is grouped, constraints should apply to the group)

crm configure colocation haproxyWithIPs INFINITY: haproxy_wwwLoadBalance haproxy_wwwSharedIP

IP-address should be up before haproxy starts.

crm configure order haproxyAfterIPs mandatory: haproxy_wwwSharedIP haproxy_wwwLoadBalance

Test it

while true; do wget --quiet http://www/ -O /dev/stdout; sleep 1; done

References

None: Corosync and HA-proxy (last edited 2021-08-12 09:31:08 by Kristian Kallenberg)

-  ⇤ ← Revision 5 as of 2018-01-09 23:41:44 → 
  Size: 657
  Editor: Kristian Kallenberg
  Comment:
+   ← Revision 46 as of 2020-01-30 21:20:49 → ⇥
  Size: 4246
  Editor: Kristian Kallenberg
  Comment:
-Deletions are marked like this.
+Additions are marked like this.
 Line 1:
-= Corosync =
We will use corosync to create a virtual IP-address which is shared by two systems. One of the systems has the virtual IP-address. If the system goes down, the other system will take over the virtual IP-address.
+= Corosync and HA-proxy =
-Line 4:
+Line 3:
- * 192.168.1.47 virtual IP-address
+We will use corosync to create a virtual IP-address which is shared by two systems. One of the systems has the virtual IP-address. If the system goes down, the other system will take over the virtual IP-address. HA-proxy will be running on each of the hosts relaying incoming HTTP-requests to two webservers.

 * 192.168.1.49 www (virtual IP-address)
-Line 10:
+Line 11:
-apt-get install corosync
+apt-get install corosync haproxy crmsh
-Line 14:
+Line 15:
-Add the local network and a multicast address to `/etc/corosync/corosync.conf` in the `interface` section
+Before binding to the DNS name `www` make sure the DNS server knows that name. There is no physical or virtual network interfaces, so the [[DNS Updates|DNS updates]] has to be done manually.

=== Corosync ===

==== Encryption ====
Edit `/etc/corosync/corosync.conf` and make the following changes.
{{{
totem {
        crypto_cipher: aes256
        crypto_hash: sha512
}
}}}

==== Authentication Key ====
Generate the authkey. Note that this requires entropy, so use your system and the entropy will be generated. Speed this up by running `dd if=/dev/vda of=/dev/null` in another terminal.
{{{
corosync-keygen
}}}

==== Network ====
Add the local network and a multicast address to `/etc/corosync/corosync.conf` in the `interface` section.
-Line 21:
+Line 42:
+Copy the configuration `/etc/corosync/corosync.conf` and the authkey `/etc/corosync/authkey` to the other host.
-Line 22:
+Line 44:
-== Commmands ==
Run the following on startup
+Restart corosync on both hosts to load the new configuration.
-Line 25:
+Line 46:
+service corosync restart
}}}
-Line 26:
+Line 49:
+=== HA-proxy ===

==== HA-proxy resource script ====
Download the HA-proxy resource script, place it in `/usr/lib/ocf/resource.d/heartbeat/haproxy` and make it executeable.
{{{
wget https://raw.githubusercontent.com/thisismitch/cluster-agents/master/haproxy -O /usr/lib/ocf/resource.d/heartbeat/haproxy
chmod +x /usr/lib/ocf/resource.d/heartbeat/haproxy
-Line 27:
+Line 57:
+This has to be done on both hosts.

==== Webfarm ====

Add the following to `/etc/haproxy/haproxy.cfg`
{{{
listen webfarm 
        bind www:80
        mode http
        balance roundrobin
        cookie LBN insert indirect nocache
        option httpclose
        option forwardfor
        server haproxy01 www01:80 cookie node1 check
        server haproxy02 www02:80 cookie node2 check
}}}
Copy the configuration `/etc/haproxy/haproxy.cfg` to the other host.

Restart HA-proxy on both hosts to load the new configuration.
{{{
service haproxy restart
}}}

==== Nodes ====
Do not kill the other node.
{{{
crm configure property stonith-enabled=false
}}}
Disable quorum due to two nodes only.
{{{
crm configure property no-quorum-policy=ignore
}}}
Configure shared IP-address.
{{{
crm configure primitive haproxy_wwwSharedIP ocf:heartbeat:IPaddr2 params ip=192.168.1.49 cidr_netmask=24 op monitor interval=5s
}}}
Create heartbeat for haproxy.
{{{
crm configure primitive haproxy_wwwLoadBalance ocf:heartbeat:haproxy params conffile=/etc/haproxy/haproxy.cfg op monitor interval=10s
}}}
Make sure the same server has both IP and service at the same time.
{{{
crm configure group haproxy_www haproxy_wwwSharedIP haproxy_wwwLoadBalance
}}}
Create the relation between IP-address and haproxy servers.

currently gives:
root@haproxy01:/etc/corosync# crm configure colocation haproxyWithIPs INFINITY: haproxy_wwwLoadBalance haproxy_wwwSharedIP

WARNING: haproxyWithIPs: resource haproxy_wwwLoadBalance is grouped, constraints should apply to the group

WARNING: haproxyWithIPs: resource haproxy_wwwSharedIP is grouped, constraints should apply to the group)

{{{
crm configure colocation haproxyWithIPs INFINITY: haproxy_wwwLoadBalance haproxy_wwwSharedIP
}}}
IP-address should be up before haproxy starts.
{{{
crm configure order haproxyAfterIPs mandatory: haproxy_wwwSharedIP haproxy_wwwLoadBalance
}}}

== Test it ==
{{{
while true; do wget --quiet http://www/ -O /dev/stdout; sleep 1; done
}}}

== References ==
 * https://wiki.debian.org/Debian-HA/ClustersFromScratch
 * https://www.digitalocean.com/community/tutorials/how-to-create-a-high-availability-setup-with-corosync-pacemaker-and-floating-ips-on-ubuntu-14-04