Forum Discussion
Pool member with sporadically listening service
- Jul 05, 2019
I recommend looking at how fast your monitor is configured to be (un)available. I recommend tcp_half_open (it's faster).
A very agressive monitor could be configured:
Interval: 1
Up interval: Disabled (it'll be online as soon as a succesful reply is received)
Time Until Up: 0
Time out: (however long you want the service to be available even when there's no successful response)
Manual resume: No
Additionally; you could add an alias service port. If the pool member is 10.10.10.10:4401 but the health monitor is to check 4402, you could specifiy 4402 in your monitor.
if an active pool member starts to listen on a port - how fast is F5 expected to connect to it
However fast your monitor interval + monitor up time + pool slow ramp combination is
Slow Ramp shouldn't prevent traffic as the intention described shouldn't generate too much of it... but you never know.
Possible troubleshooting:
Verify that you haven't configured a connection limit
There's a nice little tool called tcping (for windows). In cmd/powershell try running it before starting the service. Then you can see how quickly the vIP is online.
.\tcping.exe -t 10.10.10.10 4402
The mcpd process reports in your ltm log when it sees them member back online.
I recommend looking at how fast your monitor is configured to be (un)available. I recommend tcp_half_open (it's faster).
A very agressive monitor could be configured:
Interval: 1
Up interval: Disabled (it'll be online as soon as a succesful reply is received)
Time Until Up: 0
Time out: (however long you want the service to be available even when there's no successful response)
Manual resume: No
Additionally; you could add an alias service port. If the pool member is 10.10.10.10:4401 but the health monitor is to check 4402, you could specifiy 4402 in your monitor.
if an active pool member starts to listen on a port - how fast is F5 expected to connect to it
However fast your monitor interval + monitor up time + pool slow ramp combination is
Slow Ramp shouldn't prevent traffic as the intention described shouldn't generate too much of it... but you never know.
Possible troubleshooting:
Verify that you haven't configured a connection limit
There's a nice little tool called tcping (for windows). In cmd/powershell try running it before starting the service. Then you can see how quickly the vIP is online.
.\tcping.exe -t 10.10.10.10 4402
The mcpd process reports in your ltm log when it sees them member back online.
One more update: I tested the service port alias using a different port and that works even better. No delay or monitor interval adjustments needed. As long as the alias port is continuously up the connection to port 4402 is set up immediately, which solves my problem.
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