Hi,
I just deployed a test cluster to try that out, too. I only deployed
three MONs, but this should also apply.
I tried to create the third datacenter and put the
tiebreaker there but got
the following error:
----------------------------------------------------
root@ceph-node-01:/home/clouduser# ceph mon enable_stretch_mode
ceph-node-05 stretch_rule datacenter
Error EINVAL: there are 3datacenter's in the cluster but stretch mode
currently only works with 2!
You don't create a third datacenter within the osd tree, you just tell
ceph that your tie-breaker is in a different dc. For me it worked, I
have two DCs and put the third (tie-breaker) into (virtual) dc3:
pacific1:~ # ceph mon set_location pacific3 datacenter=dc3
pacific1:~ # ceph mon enable_stretch_mode pacific3 stretch_rule datacenter
This automatically triggered pool size 4 and distributed the PGs
evenly across both DCs.
Regards,
Eugen
Zitat von Felix O <hostorig(a)gmail.com>om>:
> Hello,
>
> I'm trying to deploy my test ceph cluster and enable stretch mode (
>
https://docs.ceph.com/en/latest/rados/operations/stretch-mode/). My problem
> is enabling the stretch mode.
> ----------------------------------------------------
> $ ceph mon enable_stretch_mode ceph-node-05 stretch_rule datacenter
> Error EINVAL: Could not find location entry for datacenter on monitor
> ceph-node-05
> ----------------------------------------------------
> ceph-node-5 is the tiebreaker monitor
>
I tried to create the third datacenter and put the
tiebreaker there but got
the following error:
----------------------------------------------------
root@ceph-node-01:/home/clouduser# ceph mon enable_stretch_mode
ceph-node-05 stretch_rule datacenter
Error EINVAL: there are 3datacenter's in the cluster but stretch mode
currently only works with 2!
>
----------------------------------------------------
> An additional info:
> ----------------------------------------------------
> Setup method: cephadm (
https://docs.ceph.com/en/latest/cephadm/install/)
>
> # ceph osd tree
> ID CLASS WEIGHT TYPE NAME STATUS REWEIGHT PRI-AFF
> -1 0.03998 root default
> -11 0.01999 datacenter site1
> -5 0.00999 host ceph-node-01
> 0 hdd 0.00999 osd.0 up 1.00000 1.00000
> -3 0.00999 host ceph-node-02
> 1 hdd 0.00999 osd.1 up 1.00000 1.00000
> -12 0.01999 datacenter site2
> -9 0.00999 host ceph-node-03
> 3 hdd 0.00999 osd.3 up 1.00000 1.00000
> -7 0.00999 host ceph-node-04
> 2 hdd 0.00999 osd.2 up 1.00000 1.00000
>
> stretch_rule is added to the crush
>
> # ceph mon set_location ceph-node-01 datacenter=site1
> # ceph mon set_location ceph-node-02 datacenter=site1
> # ceph mon set_location ceph-node-03 datacenter=site2
> # ceph mon set_location ceph-node-04 datacenter=site2
>
> # ceph versions
> {
> "mon": {
> "ceph version 16.2.1 (afb9061ab4117f798c858c741efa6390e48ccf10)
> pacific (stable)": 5
> },
> "mgr": {
> "ceph version 16.2.1 (afb9061ab4117f798c858c741efa6390e48ccf10)
> pacific (stable)": 2
> },
> "osd": {
> "ceph version 16.2.1 (afb9061ab4117f798c858c741efa6390e48ccf10)
> pacific (stable)": 4
> },
> "mds": {},
> "overall": {
> "ceph version 16.2.1 (afb9061ab4117f798c858c741efa6390e48ccf10)
> pacific (stable)": 11
> }
> }
>
> Thank you for your support.
>
> --
> Best regards,
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