KB 2444: HIGH AVAILABILITY WITH OLFEO SERVERS

How to set up high availability on Olfeo servers.

Objective

Implement high availability with the VRRP protocol in order to use a virtual IP address that enables Olfeo service continuity on one of the cluster members.

Steps

1. On the master machine, on the Settings > High Availability > Olfeo Domain page, click Add a slave:

The Slave Machine screen appears. Add the IP address of the future slave machine:

On the slave machine, enter the ID provided by the master machine and the master's IP address to join the Olfeo domain, then confirm:

A patience page will then indicate that the connection to the domain is in progress:

Log in using an administrator account on the master machine: only the menus specific to the local configuration of the machine will appear. The graphical interface now indicates that the server is in slave mode:

Refresh the Domaine Olfeo page on the master machine:the slavestatus changes to Online.

2. The second step is to create a cluster so that each member has a virtual IP address. Click on the Add Cluster link:

Enter a number between 1 and 254 in theFirst VRRP ID field. The first VRRP ID is an identifier used for node management.

For each machine previously added to the Olfeo cluster, enter a virtual IP address in the Virtual IP column.

Load balancing via proxy.pac

It is possible to distribute the load between the different nodes by implementing a proxy.pac as in one of the three examples below:

• Example 1: High availability (failover).

  function FindProxyForURL(url, host) {

  // Ne passe pas par le proxy si le host n’est pas un FQDN.
  if (isPlainHostName(host))
  return « DIRECT »;

  // Exceptions : Ne pas passer par le proxy si l’URL match les regex suivantes :
  if (shExpMatch(url, »*domain.com* ») || shExpMatch(url, »*vpn.domain.com* »))
  return « DIRECT »;

  // Ne pas passer par le proxy si les noms d’hôtes de destination sont sur le réseau local.

  var resolved_ip = dnsResolve(host);

  if (isInNet(resolved_ip, "10.0.0.0", "255.0.0.0") || 'perform replication
  isInNet(resolved_ip, "172.16.0.0", "255.240.0.0") ||
  isInNet(resolved_ip, "192.168.0.0", "255.255.0.0") ||
  isInNet(resolved_ip, "127.0.0.0", "255.255.255.0"))
  return "DIRECT";

  // Ne pas passer par le proxy entreprise si l’utilisateur n’est pas connecté au LAN entreprise.
  if (!isInNet(myIpAddress(), « 10.10.1.0 », « 255.255.255.0 »))
  return « DIRECT »;

  // Tout le reste passe par le proxy entreprise.
  //exemple 1 : Un seul proxy :
  return « PROXY proxy.mondomaine.tld:3129 »;

  //exemple 2 : 2 proxy en Fail Over
  // return « PROXY proxy1.mondomaine.tld:3129; PROXY proxy2.mondomaine.tld:3129; DIRECT »;
  }

• Example 2: Using a specific proxy depending on the protocol used.

  function FindProxyForURL(url, host) {

  // Si l’hôte de destination (FQDN ou IP) est interne : ne pas passer par le proxy.

  var resolved_ip = dnsResolve(host);

  if (isInNet(resolved_ip, "10.0.0.0", "255.0.0.0") ||
  isInNet(resolved_ip, "172.16.0.0", "255.240.0.0") ||
  isInNet(resolved_ip, "192.168.0.0", "255.255.0.0") ||
  isInNet(resolved_ip, "127.0.0.0", "255.255.255.0"))
  return "DIRECT";

  // Utiliser un proxy différent en fonction du protocole.
  if (shExpMatch(url, « http:* »))  return « PROXY proxy1.mondomain.tld:3129 »;
  if (shExpMatch(url, « https:* »)) return « PROXY proxy2.mondomain.tld:3129 »;
  if (shExpMatch(url, « ftp:* »)) return « PROXY proxy3.mondomain.tld:3129 »;

  }

• Example 3: load balancing.

  function FindProxyForURL(url, host)
  {// Ne passe pas par le proxy si le host n’est pas un FQDN.
  if (isPlainHostName(host))
  return « DIRECT »;

  // Exceptions : ne pas passer par le proxy si l’URL match les regex suivantes.
  if (shExpMatch(url, »*domain.com* ») || shExpMatch(url, »*vpn.domain.com* »))
  return « DIRECT »;

  // Ne pas passer par le proxy si les noms d’hôtes de destination sont internes.

  var resolved_ip = dnsResolve(host);

  if (isInNet(resolved_ip, "10.0.0.0", "255.0.0.0") ||
  isInNet(resolved_ip, "172.16.0.0", "255.240.0.0") ||
  isInNet(resolved_ip, "192.168.0.0", "255.255.0.0") ||
  isInNet(resolved_ip, "127.0.0.0", "255.255.255.0"))
  return "DIRECT";

  // Ne pas passer par le proxy entreprise si l’utilisateur n’est pas connecté au LAN entreprise.
  if (!isInNet(myIpAddress(), « 10.10.1.0 », « 255.255.255.0 »))
  return « DIRECT »;

  // On retourne une chaîne de proxy en fonction du hash de l’URL modulo le nombre de proxy. Ceci permet d’obtenir à la fois une répartition de charge et une tolérance aux pannes.
  ret = URLhash(url);

  if ( (ret % 2) == 0 ) {
  return « PROXY proxy1.mondomaine.tld:3129 ; PROXY proxy2.mondomaine.tld:3129  » ;
  } else  {
  return « PROXY proxy2.mondomaine.tld:3129 ; PROXY proxy1.mondomaine.tld:3129  » ;
  }

  }

  function URLhash(name)
  {
  var  cnt=0;
  var str=name.toLowerCase(name);

  if ( str.length ==0) {
  return cnt;
  }

  for(var i=0;i < str.length ; i++) {
  var ch= atoi(str.substring(i,i + 1));
  cnt = cnt + ch;
  }

  return cnt;
  }

  function atoi(charstring)
  {

  if (charstring == "a") return 0x61; if (charstring == "b") return 0x62;
  if (charstring == "c") return 0x63; if ( charstring == "d") return 0x64;
  if ( charstring == "e") return 0x65; if ( charstring == "f") return 0x66;
  if ( charstring == "g") return 0x67; if ( charstring == "h") return 0x68;
  if ( charstring == "i") return 0x69; if ( charstring == "j") return 0x6a;
  if ( charstring == "k") return 0x6b; if ( charstring == "l") return 0x6c;
  if ( charstring == "m") return 0x6d; if ( charstring == "n" ) return 0x6e;
  if ( charstring == "o" ) return 0x6f; if ( charstring == "p" ) return 0x70;
  if ( charstring == "q" ) return 0x71; if ( charstring == "r" ) return 0x72;
  if ( charstring == "s") return 0x73; if ( charstring == "t") return 0x74;
  if ( charstring == "u") return 0x75; if ( charstring == "v") return 0x76;
  if ( charstring == "w") return 0x77; if ( charstring == "x" ) return 0x78;
  if ( charstring == "y" ) return 0x79; if ( charstring == "z" ) return 0x7a;
  if ( charstring == "0" ) return 0x30; if ( charstring == "1" ) return 0x31;
  if ( charstring == "2" ) return 0x32; if ( charstring == "3" ) return 0x33;
  if ( charstring == "4" ) return 0x34; if ( charstring == "5" ) return 0x35;
  if ( charstring == "6" ) return 0x36; if ( charstring == "7" ) return 0x37;
  if ( charstring == "8" ) return 0x38; if ( charstring == "9" ) return 0x39;
  if ( charstring == "." ) return 0x2e;
  return 0x20;
  }

Validation

• Use the "ip a" command rather than "ifconfig" for an accurate reading of virtual IP settings.
• Check the IP configuration of each cluster member; each cluster member must have two IP addresses (one physical and one virtual).
• On the master server, stop the keepalived service (/etc/init.d/keepalived stop). The slave server must retrieve the virtual IP address from the master.
• Restart the keepalive service on the master server (/etc.init.d/keepalived start). The master server must retrieve its virtual IP address, and the slave must not retain it.