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.

totem {
        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. 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
}

Restart corosync to load the new configuration.

service corosync restart

Nodes

THIS WORKS Do not kill the other node.

crm configure property stonith-enabled=false

THIS HAS TO BE TESTED

# disable quorum due to two nodes only
crm configure property no-quorum-policy=ignore
# configure shared IP
crm configure primitive haproxySharedIP  ocf:heartbeat:IPaddr2 params ip=192.168.1.47 cidr_netmask=24 op monitor interval=5s
# create heartbeat for haproxy
crm configure primitive haproxyLoadBalance ocf:heartbeat:haproxy params conffile=/etc/haproxy/haproxy.cfg op monitor interval=10s

# make sure the same server has both IP and service
#crm configure group haproxyIPs haproxySharedIP meta ordered=false
crm configure group haproxy haproxySharedIP haproxyLoadBalance
# relation between IP and haproxy servers
crm configure colocation haproxyWithIPs INFINITY: haproxyLoadBalance haproxySharedIP
# IP should be up before haproxy starts
crm configure order haproxyAfterIPs mandatory: haproxySharedIP haproxyLoadBalance 
#wget http://github.com/russki/cluster-agents/raw/master/haproxy
#echo "net.ipv4.ip_nonlocal_bind = 1" >> /etc/sysctl.conf

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 16 as of 2018-01-20 13:23:12 → 
  Size: 2827
  Editor: Kristian Kallenberg
  Comment:
+   ← Revision 27 as of 2018-01-20 15:28:21 → ⇥
  Size: 3126
  Editor: Kristian Kallenberg
  Comment:
-Deletions are marked like this.
+Additions are marked like this.
 Line 20:
-==== 
edit `/etc/corosync/corosync.conf` and make the following changes.
+==== Encryption ====
Edit `/etc/corosync/corosync.conf` and make the following changes.
-Line 23:
+Line 24:
-crypto_cipher: aes256
crypto_hash: sha512
+totem {
        crypto_cipher: aes256
        crypto_hash: sha512
}
-Line 27:
+Line 30:
+==== Certificates ====
Generate the certificates. 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
}
}}}

Restart corosync to load the new configuration.
{{{
service corosync restart
}}}

==== Nodes ====
THIS WORKS
Do not kill the other node.
{{{
crm configure property stonith-enabled=false
}}}

THIS HAS TO BE TESTED
{{{
# disable quorum due to two nodes only
crm configure property no-quorum-policy=ignore
# configure shared IP
crm configure primitive haproxySharedIP  ocf:heartbeat:IPaddr2 params ip=192.168.1.47 cidr_netmask=24 op monitor interval=5s
# create heartbeat for haproxy
crm configure primitive haproxyLoadBalance ocf:heartbeat:haproxy params conffile=/etc/haproxy/haproxy.cfg op monitor interval=10s

# make sure the same server has both IP and service
#crm configure group haproxyIPs haproxySharedIP meta ordered=false
crm configure group haproxy haproxySharedIP haproxyLoadBalance
# relation between IP and haproxy servers
crm configure colocation haproxyWithIPs INFINITY: haproxyLoadBalance haproxySharedIP
# IP should be up before haproxy starts
crm configure order haproxyAfterIPs mandatory: haproxySharedIP haproxyLoadBalance 
#wget http://github.com/russki/cluster-agents/raw/master/haproxy
#echo "net.ipv4.ip_nonlocal_bind = 1" >> /etc/sysctl.conf

}}}
-Line 49:
+Line 99:
-=== Corosync ===
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
}
}}}
-Line 58:
+Line 100:
-Restart corosync to load the new configuration.
{{{
service corosync restart
}}}
-Line 63:
+Line 101:
-== Commmands ==
Run the following on startup
{{{#!highlight bash
# do not kill 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
crm configure primitive haproxySharedIP  ocf:heartbeat:IPaddr2 params ip=192.168.1.47 cidr_netmask=24 op monitor interval=5s
# create heartbeat for haproxy
crm configure primitive haproxyLoadBalance ocf:heartbeat:haproxy params conffile=/etc/haproxy/haproxy.cfg op monitor interval=10s

# make sure the same server has both IP and service
#crm configure group haproxyIPs haproxySharedIP meta ordered=false
crm configure group haproxy haproxySharedIP haproxyLoadBalance
# relation between IP and haproxy servers
crm configure colocation haproxyWithIPs INFINITY: haproxyLoadBalance haproxySharedIP
# IP should be up before haproxy starts
crm configure order haproxyAfterIPs mandatory: haproxySharedIP haproxyLoadBalance 
#wget http://github.com/russki/cluster-agents/raw/master/haproxy
#echo "net.ipv4.ip_nonlocal_bind = 1" >> /etc/sysctl.conf

}}}