[PVE-User] dual host HA solution in 5.2

[Adam Weremczuk]

Hi all,

I have 2 identical servers, each having 4 NICs + Management and 15 x 
500GB disks.

I'm trying Proxmox VE 5.2 and just found out the default recommended HA 
solution requires 3 hosts, which I don't have.

I'm only planning to stick to Debian stretch and LXC containers.

I have the following architecture in mind on each:

- RAID1 virtual disk (2 disks) - 500GB space for Proxmox and containers 
(Samba AD, LDAP, Cyrus mail, MySQL and a few more).

I will try to import pre-baked Turnkey Linux server apps: 
https://www.turnkeylinux.org/all

If there is insufficient space they start using storage which will be:

- RAID50 (6 + 6 disks) + 1 hot spare virtual disk - 5 TB of storage 
space. This disk will be synced between servers over 2 directly 
connected bonded gigabit links using DRBD/pacemaker/corosys.

Something similar to: 
https://www.theurbanpenguin.com/drbd-pacemaker-ha-cluster-ubuntu-16-04/

- each host is connected to a core switch with 2 bonded gigabit links 
using LAG/LACP (this is already in place and working nicely).

- LXC containers will be kept in sync on application level (2 domain 
controllers, MySQL replication etc.)

- everything will be backed up by a dedicated Bacula server to LTO tapes 
with off site rotation.

I should be able to take one node offline at any time.

If I pause storage replication beforehand then it should cause no 
disruptions.

If the master node goes boom without warning then I guess  some downtime 
is possible.

E.g. if the slave storage needs to run some consistency / filesystem check.

With my solution I'm not too concerned about performance or few hours of 
downtime.

But data loss or prolonged outages are unacceptable.

Please advise if you have better ideas!


Regards,
Adam