Administrative Status on F5 BIG-IP LTM Load Balancer

Administrative Status

Monitors perform tests on nodes and members. The results may dynamically change the state of a Node Member, Pool or Virtual Server any time.

When an administrative needs to gracefully stop BIG-IP from sending client traffic to a Node or member, they need to change administrative state of the node, pool member or Virtual server.

The default administrative state is enabled. This status accepts all types of traffic. New connections Persistent session and open existing connections.

All administrative states accept traffic from open existing connections. The disable state also accepts traffic from new connections, but only from returning clients within the time out period. This means from clients that match a BIG-IP Persistence record.

A Node and Pool member in the forced offline state only services traffic from open existing connections. The disabled and forced offline states differ only when persistence is involved.

Again all administrative states accept traffic from any open existing client connections, at least until the connection terminates or time out. If a monitor has marked a Node or pool member offline that is different, and no client traffic is sent.

A virtual server’s administrative state can only be changed between enabled and disabled.

 3 Administrative States

Administrative States icons

In the enabled administrative state-Monitor checks are used to determine Nodes and members state. Pools an virtual server states are determined from the inherited status of the nodes and members. Monitor and administrator status can be viewed from the statistics and Network map screens.

To indicate that a node or members administrative state is now disabled, BIG-IP changes the icon colour to black while maintaining its previous monitor status Icon shape.

To indicate that the node or members administrative state is now off line, BIG-IP changes the Icon to a Black Diamond

A disabled and forced offline Node or a member share the same black diamond status icon only if the monitor status was offline also. So distinguish the Icon between two is

Disabledà Iconà Pool member has been marked down by a monitor.

Disabled State

lets look at the Disabled Administrative state and its impact on the state of the pool and virtual server

Ex: -

In this example, all of the member most resent monitors check was successful, so all were available as was the pool and virtual server.

Now two  members have been disabled, but the pool and virtual server are still marked available.

Even after the last member is disabled, the pool and virtual server and virtual server are still marked available because they will need to process client traffic for open existing connections and supports new connections from client matching existing persistence records.

Forced Offline State

 Now lets load at the forced offline administrative state and its impact on the state of pool and virtual server.

Ex:-

In this example, the first member’s most recent checks was successful, so its status is available, while the other members have just been Forced Offline.

This results in the pool and virtual server still being marked available.

When the first member will maintain open existing client connections, but since there are no pool members available for new connections, both the pool and virtual server are marked offline also.

Changing Pool Member State

To administratively change the state of pool member expand local traffic from the navigation panel and select Pools. Select Members tab and then select a member.

The state of a Pool Member can be changed by selecting one of the state options.

A member can also be enabled or disabled but not forced offline from the current members list.