Cluster and quorum....

[diaolin]

Hi, i have two machines correctly seen when they are up and running but, when i start only one of the two and i probe creating a new VM i have an error:

Boot: Starting cluster OK
Starting cman OK
all oK until quorum that obviously says:

Waiting for quorum... timed out...
[FAILED]
Cluster not ready - no quorum?


when i try to create a new KVM machine the interface says

cluster not ready - no quorum? (500)

Why?
It's unpossible creating a new machine without cluster?

I-ve found that /etc/pve is readonly...

Tx, Diaolin

 

[tom]

without quorum you cannot do anything, that´t the concept and the expected behavior. do you have a two node setup? do you use a qdisk?

 

[diaolin]

two node setup...
but when a node is down writing on /etc/pve is disabled

 

[tom]

it seems that you do not understand the basic nature of a cluster and a quorum. and you did not answer my questions. do you have a quorum disk?

if a two node cluster is divided, each node have just one vote. its a "democratic" system, so with a two node cluster you end in unresolved situation. each node have one vote and no node have a majority of votes (1:1)

so either use at least 3 nodes or took the right measures for a 2 node system (e.g. configure a quorum disk)

 

[diaolin]

Ah, ok
now i undestand my trouble.
I don't have a quorum disk. But, do you think that is possible to have a quorum disk with two nodes without a dedicated separate storage?
Tx

 

[dietmar]

Ah, ok
now i undestand my trouble.
I don't have a quorum disk. But, do you think that is possible to have a quorum disk with two nodes without a dedicated separate storage?

No, a quorum disk needs some sort of shared storage.

Note: It is also possible to assign 2 votes to one node.

 

[squeeb]

Go on...? .. How does one do that?

 

[OO-Dragon]

Go on...? .. How does one do that?

I seemed to have figured out how.

on both servers, run

/etc/init.d/pve-cluster stop

then

/usr/bin/pmxcfs -l

then edit both configs on both machines to change votes

nano /etc/pve/cluster.conf

You'll see your 2 servers, just edit the same one on both servers to have a vote of 2 and the other leave as 1. Save the configs and reboot the systems. Should be fine and dandy.

 

[jva1601]

Thanks OO-Dragon that fixed mine too which broke after doing an upgrade.

 

[dietmar]

If you want to force quorum, you can simply set the expected votes to 1:

# pvecm expected 1

 

[OO-Dragon]

If you want to force quorum, you can simply set the expected votes to 1:

# pvecm expected 1

I tried that originally but it wouldn't connect because cman wouldn't stay running due to quorum timing out. Or do you mean just run with local pmxcfs then do that command?

 

[MikeP]

If you want to force quorum, you can simply set the expected votes to 1:

# pvecm expected 1

For a test cluster, I have 2 nodes. One of them is offline. So, following this, I checked

#pvecm status
### this showed that expected was 2 for 2 nodes.
#pvecm expected 1
#pvecm status
### this now shows expected as 1.
### this lets me run with only 1 of the 2 working. This is not recommended for production nor HA, but is great for my home lab with two boxes, so I don't need to power them both on all the time.

 

[netdesignate]

For a test cluster, I have 2 nodes. One of them is offline. So, following this, I checked
### this lets me run with only 1 of the 2 working.
This is not recommended for production nor HA, but is great for my home lab with two boxes, so I don't need to power them both on all the time.

This was a very useful post for me - THANKS MikeP