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.

192.168.1.47 www (virtual IP-address)
192.168.1.48 haproxy01
192.168.1.49 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.

crypto_cipher: aes256
crypto_hash: sha512

Certificates

Generate the certificates. Note that this requires entropy, so use your system and the entropy will be generated.

corosync-keygen

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
}

Restart corosync to load the new configuration.

service corosync restart

Commmands

Run the following on startup

   1 # do not kill other node
   2 crm configure property stonith-enabled=false
   3 # disable quorum due to two nodes only
   4 crm configure property no-quorum-policy=ignore
   5 # configure shared IP
   6 crm configure primitive haproxySharedIP  ocf:heartbeat:IPaddr2 params ip=192.168.1.47 cidr_netmask=24 op monitor interval=5s
   7 # create heartbeat for haproxy
   8 crm configure primitive haproxyLoadBalance ocf:heartbeat:haproxy params conffile=/etc/haproxy/haproxy.cfg op monitor interval=10s
   9 
  10 # make sure the same server has both IP and service
  11 #crm configure group haproxyIPs haproxySharedIP meta ordered=false
  12 crm configure group haproxy haproxySharedIP haproxyLoadBalance
  13 # relation between IP and haproxy servers
  14 crm configure colocation haproxyWithIPs INFINITY: haproxyLoadBalance haproxySharedIP
  15 # IP should be up before haproxy starts
  16 crm configure order haproxyAfterIPs mandatory: haproxySharedIP haproxyLoadBalance 
  17 #wget http://github.com/russki/cluster-agents/raw/master/haproxy
  18 #echo "net.ipv4.ip_nonlocal_bind = 1" >> /etc/sysctl.conf
  19

HA-proxy

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

Restart HA-proxy

service haproxy restart

References

https://wiki.debian.org/Debian-HA/ClustersFromScratch

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

-  ⇤ ← Revision 11 as of 2018-01-10 00:12:54 → 
  Size: 2455
  Editor: Kristian Kallenberg
  Comment:
+   ← Revision 19 as of 2018-01-20 13:35:20 → ⇥
  Size: 3002
  Editor: Kristian Kallenberg
  Comment:
-Deletions are marked like this.
+Additions are marked like this.
 Line 1:
+Incomplete, do not use!
-Line 15:
+Line 17:
-Before binding to the DNS name `www` make sure the DNS server knows that name.
 
=== HA-proxy ===
Add the following to `/etc/haproxy/haproxy.cfg`
+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.
-Line 20:
+Line 24:
-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
+crypto_cipher: aes256
crypto_hash: sha512
-Line 31:
+Line 28:
-Restart HA-proxy
+==== Certificates ====
Generate the certificates. Note that this requires entropy, so use your system and the entropy will be generated.
-Line 33:
+Line 31:
-service haproxy restart
+corosync-keygen
-Line 36:
+Line 34:
-=== Corosync ===
-Line 73:
+Line 71:
+=== HA-proxy ===
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
}}}

Restart HA-proxy
{{{
service haproxy restart
}}}




== References ==
  * https://wiki.debian.org/Debian-HA/ClustersFromScratch