Re: [ClusterLabs] colocation constraint - do I get it all wrong?
On Mon, Feb 5, 2024 at 12:44 PM lejeczek via Users wrote: > > > > On 01/01/2024 18:28, Ken Gaillot wrote: > > On Fri, 2023-12-22 at 17:02 +0100, lejeczek via Users wrote: > >> hi guys. > >> > >> I have a colocation constraint: > >> > >> -> $ pcs constraint ref DHCPD > >> Resource: DHCPD > >>colocation-DHCPD-GATEWAY-NM-link-INFINITY > >> > >> and the trouble is... I thought DHCPD is to follow GATEWAY-NM-link, > >> always! > >> If that is true that I see very strange behavior, namely. > >> When there is an issue with DHCPD resource, cannot be started, then > >> GATEWAY-NM-link gets tossed around by the cluster. > >> > >> Is that normal & expected - is my understanding of _colocation_ > >> completely wrong - or my cluster is indeed "broken"? > >> many thanks, L. > >> > > Pacemaker considers the preferences of colocated resources when > > assigning a resource to a node, to ensure that as many resources as > > possible can run. So if a colocated resource becomes unable to run on a > > node, the primary resource might move to allow the colocated resource > > to run. > So what is the way to "fix" this - is it simply low/er score > for such constraint? > In my case _dhcpd_ is important but if fails sometimes as > it's often tampered with, so... make _dhcpd_ flow > gateway_link but just fail _dhcp_ (it it keeps failing) and > leave _gateway_link_ alone if/where it's good. > Or perhaps there a global config/param for whole cluster > behaviour? > In the current pacemaker (since 2.1.0) you can set "influence" colocation attribute to avoid moving already started resource: However, if influence is set to false in the colocation constraint, this will happen only if B is inactive and needing to be started. If B is already active, A’s preferences will have no effect on placing B. ___ Manage your subscription: https://lists.clusterlabs.org/mailman/listinfo/users ClusterLabs home: https://www.clusterlabs.org/
Re: [ClusterLabs] colocation constraint - do I get it all wrong?
On 01/01/2024 18:28, Ken Gaillot wrote: On Fri, 2023-12-22 at 17:02 +0100, lejeczek via Users wrote: hi guys. I have a colocation constraint: -> $ pcs constraint ref DHCPD Resource: DHCPD colocation-DHCPD-GATEWAY-NM-link-INFINITY and the trouble is... I thought DHCPD is to follow GATEWAY-NM-link, always! If that is true that I see very strange behavior, namely. When there is an issue with DHCPD resource, cannot be started, then GATEWAY-NM-link gets tossed around by the cluster. Is that normal & expected - is my understanding of _colocation_ completely wrong - or my cluster is indeed "broken"? many thanks, L. Pacemaker considers the preferences of colocated resources when assigning a resource to a node, to ensure that as many resources as possible can run. So if a colocated resource becomes unable to run on a node, the primary resource might move to allow the colocated resource to run. So what is the way to "fix" this - is it simply low/er score for such constraint? In my case _dhcpd_ is important but if fails sometimes as it's often tampered with, so... make _dhcpd_ flow gateway_link but just fail _dhcp_ (it it keeps failing) and leave _gateway_link_ alone if/where it's good. Or perhaps there a global config/param for whole cluster behaviour? ___ Manage your subscription: https://lists.clusterlabs.org/mailman/listinfo/users ClusterLabs home: https://www.clusterlabs.org/
Re: [ClusterLabs] colocation constraint - do I get it all wrong?
On Fri, 2023-12-22 at 17:02 +0100, lejeczek via Users wrote: > hi guys. > > I have a colocation constraint: > > -> $ pcs constraint ref DHCPD > Resource: DHCPD > colocation-DHCPD-GATEWAY-NM-link-INFINITY > > and the trouble is... I thought DHCPD is to follow GATEWAY-NM-link, > always! > If that is true that I see very strange behavior, namely. > When there is an issue with DHCPD resource, cannot be started, then > GATEWAY-NM-link gets tossed around by the cluster. > > Is that normal & expected - is my understanding of _colocation_ > completely wrong - or my cluster is indeed "broken"? > many thanks, L. > Pacemaker considers the preferences of colocated resources when assigning a resource to a node, to ensure that as many resources as possible can run. So if a colocated resource becomes unable to run on a node, the primary resource might move to allow the colocated resource to run. -- Ken Gaillot ___ Manage your subscription: https://lists.clusterlabs.org/mailman/listinfo/users ClusterLabs home: https://www.clusterlabs.org/
[ClusterLabs] colocation constraint - do I get it all wrong?
hi guys. I have a colocation constraint: -> $ pcs constraint ref DHCPD Resource: DHCPD colocation-DHCPD-GATEWAY-NM-link-INFINITY and the trouble is... I thought DHCPD is to follow GATEWAY-NM-link, always! If that is true that I see very strange behavior, namely. When there is an issue with DHCPD resource, cannot be started, then GATEWAY-NM-link gets tossed around by the cluster. Is that normal & expected - is my understanding of _colocation_ completely wrong - or my cluster is indeed "broken"? many thanks, L.___ Manage your subscription: https://lists.clusterlabs.org/mailman/listinfo/users ClusterLabs home: https://www.clusterlabs.org/
