phys/consul: Allow tuning of session ttl and lock wait time

[vishalnayak]

Fixes: #2949

Even after setting the session_ttl to "2s" and lock_wait_time to "2s", I am observing a 16s-18s delay in assuming active duty by the standby. I guess it is because of the doubling and jitter logics in Consul. It is certainly better then the ~45s delay observed without this change.

Note that the consul server imposes a lower limit of 10s on the session_ttl by default, which is applicable to the session_ttl in the lock options. In order to test this, consul server configuration should be overriding the session_ttl_min to a lower value.

[jefferai]

LGTM, but can you check w/Consul team about whether your observed behavior is in fact expected?

One other thing: Please use parseutil.ParseDuration instead of time.ParseDuration as it better handles bare strings -- time.ParseDuration will consider it to be nanoseconds instead of seconds, which is likely not what the user expects.

[jefferai]

Related to my other comment, there's somewhere else that time.ParseDuration is already used, please update that too!

[lulianbing58]

Fixes: #2949

Even after setting the session_ttl to "2s" and lock_wait_time to "2s", I am observing a 16s-18s delay in assuming active duty by the standby. I guess it is because of the doubling and jitter logics in Consul. It is certainly better then the ~45s delay observed without this change.

Note that the consul server imposes a lower limit of 10s on the session_ttl by default, which is applicable to the session_ttl in the lock options. In order to test this, consul server configuration should be overriding the session_ttl_min to a lower value.

I tried to set session_ttl_min =2s in consul configuration and in vault configuration, i set session_ttl=2s ,lock_wait_time=2s, but seems it still need 15s to swithover to standby.

anything more need to further tunning ?
Appreciate

[taitelman]

I also see 13seconds to standby taking leadership