[Debian-ha-maintainers] Bug#1085256: fence-agents: fence-agents package does not depend on any actual package

[Valentin Vidic]

On Thu, Nov 07, 2024 at 08:59:30AM +0100, Ferenc Wágner wrote:
> I think a good solution is taking shape here.  My thoughts:
> 
> 1. Currently pacemaker only Recommends fence-agents, so users disabling
>    Recommends must have installed it manually (unless disabled it later).
> 
> 2. Using pacemaker without fencing is possible but unsupported, so
>    tightening this dependency is reasonable given a singular alternative.
> 
> 3. Users creating their own fence agent packages should depend on
>    fence-agents-common, or install it manually for plain scripts.
> 
> 4. The xserver-xorg-video-* setup is a nice and well-known solution, if
>    all stakeholders support this setup, I'd go with it.
> 
> 6. I'd avoid having both fence-agents and fence-agents-all, or
>    fence-agent and fence-agents (for name similarity).  In the end
>    pacemaker should contain something like this, I guess:
> 
>    Depends: fence-agents-all | fence-agent
> 
>    where fence-agents-all would Depend on all agents (possibly only
>    Recommending some esoteric big ones), and all agent packages would
>    Provide fence-agents.
> 
> Would this handle all concerns?  Or should pacemaker stay with only
> Recommending the agents?

Maybe Recommends in pacemaker still fits better with the description:

    This declares a strong, but not absolute, dependency.

    The Recommends field should list packages that would be found
    together with this one in all but unusual installations.

But there might be few other complications to this plan...

For example, fence-agents-sbd can only be in Suggests because will also
install the sbd daemon. That daemon could influence the behavior of the
pacemaker cluster in unexpected ways like rebooting the node when quorum
is lost.

Another problem are the legacy stonith agents in the cluster-glue
package listed left below. Some of them like stonith:external/hetzner
might still be useful if there is no alternative in fence-agents.
But if we have cluster-glue also provide fence-agent, than
fence-agents-all will not be installed by default anymore?

stonith:apcmaster               stonith:fence_ilo2
stonith:apcmastersnmp           stonith:fence_ilo3
stonith:apcsmart                stonith:fence_ilo3_ssh
stonith:baytech                 stonith:fence_ilo4
stonith:bladehpi                stonith:fence_ilo4_ssh
stonith:cyclades                stonith:fence_ilo5
stonith:drac3                   stonith:fence_ilo5_ssh
stonith:external/drac5          stonith:fence_ilo_moonshot
stonith:external/dracmc-telnet  stonith:fence_ilo_mp
stonith:external/hetzner        stonith:fence_ilo_ssh
stonith:external/hmchttp        stonith:fence_imm
stonith:external/ibmrsa         stonith:fence_intelmodular
stonith:external/ibmrsa-telnet  stonith:fence_ipdu
stonith:external/ipmi           stonith:fence_ipmilan
stonith:external/ippower9258    stonith:fence_ipmilanplus
stonith:external/kdumpcheck     stonith:fence_ironic
stonith:external/libvirt        stonith:fence_kdump
stonith:external/nut            stonith:fence_kubevirt
stonith:external/rackpdu        stonith:fence_ldom
stonith:external/riloe          stonith:fence_legacy
stonith:external/sbd            stonith:fence_lindypdu
stonith:external/ssh            stonith:fence_lpar
stonith:external/vcenter        stonith:fence_mpath
stonith:external/vmware         stonith:fence_netio
stonith:external/xen0           stonith:fence_openstack
stonith:external/xen0-ha        stonith:fence_ovh

-- 
Valentin