I'm afraid that is not a host crash. When shutting down the guest OS, the
CloudStack agent on the host is still able to report to the management server
that the VM has stopped.
This is my point. VM-HA relies on the management sever communication with the
host agent.
Kind regards,
Paul Angus
paul.an...@shapeblue.com
www.shapeblue.com
53 Chandos Place, Covent Garden, London WC2N 4HSUK
@shapeblue
-----Original Message-----
From: Yiping Zhang <yzh...@marketo.com>
Sent: 24 May 2018 00:44
To: users@cloudstack.apache.org
Subject: Re: 4.11 without Host-HA framework
I can say for fact that VM's using a HA enabled service offering will be
restarted by CS on another host, assuming there are enough capacity/resources
in the cluster, when their original host crashes, regardless that host comes
back or not.
The simplest way to test VM HA feature with a VM instance using HA enabled
service offering is to issue shutdown command in guest OS, and watching it gets
restarted by CS manager.
On 5/23/18, 1:23 PM, "Paul Angus" <paul.an...@shapeblue.com> wrote:
Hi Jon,
Don't worry, TBH I'm dubious about those claiming to have VM-HA working
when a host crashes (but doesn't restart).
I'll check in with the guys that set values for host-ha when testing, to
see which ones they change and what they set them to.
paul.an...@shapeblue.com
www.shapeblue.com
53 Chandos Place, Covent Garden, London WC2N 4HSUK
@shapeblue
-----Original Message-----
From: Jon Marshall <jms....@hotmail.co.uk>
Sent: 23 May 2018 21:10
To: users@cloudstack.apache.org
Subject: Re: 4.11 without Host-HA framework
Rohit / Paul
Thanks again for answering.
I am a Cisco guy with an ex Unix background but no virtualisation
experience and I can honestly say I have never felt this stupid before 😊
I have Cloudstack working but failover is killing me.
When you say VM HA relies on the host telling CS the VM is down how does
that work because if you crash the host how does it tell CS anything ? And when
you say tell CS do you mean the CS manager ?
I guess I am just not understanding all the moving parts. I have had HOST
HA working (to an extent) although it takes a long time to failover even after
tweaking the timers but the fact that I keep finding references to people
saying even without HOST HA it should failover (and mine doesn't) makes me
think I have configured it incorrectly somewhere along the line.
I have configured a compute offering with HA and I am crashing the host
with the echo command as suggested but still nothing.
I understand what you are saying Paul about it not being a good idea to
rely on VM HA so I will go back to Host HA and try to speed up failover times.
Can I ask, from your experiences, what is a realistic fail over time for CS
ie. if a host fails for example ?
Jon
________________________________
From: Paul Angus <paul.an...@shapeblue.com>
Sent: 23 May 2018 19:55
To: users@cloudstack.apache.org
Subject: RE: 4.11 without Host-HA framework
Jon,
As Rohit says, it is very important to understand the difference between VM
HA and host HA.
VM HA relies on the HOST telling CloudStack that the VM is down on order
for CloudStack start it again (wherever that ends up being).
Any sequence of events that ends up with VM HA restarting the VM when
CloudStack can't contact the host is luck/fluke/unreliable/bad(tm)
The purpose of Host HA was to create a reliable mechanism to determine that
a host has 'crashed' and that the VMs within it are inoperative. Then take
appropriate action, including ultimately telling VM HA to restart the VM
elsewhere.
paul.an...@shapeblue.com
www.shapeblue.com<http://www.shapeblue.com>
Shapeblue - The CloudStack Company<http://www.shapeblue.com/>
www.shapeblue.com
ShapeBlue are the largest independent integrator of CloudStack technologies
globally and are specialists in the design and implementation of IaaS cloud
infrastructures for both private and public cloud implementations.
53 Chandos Place, Covent Garden, London WC2N 4HSUK @shapeblue
-----Original Message-----
From: Rohit Yadav <rohit.ya...@shapeblue.com>
Sent: 23 May 2018 10:45
To: users@cloudstack.apache.org
Subject: Re: 4.11 without Host-HA framework
Jon,
In the VM's compute offering, make sure that HA is ticked/enabled. Then use
that HA-enabled VM offering while deploying a VM. Around testing - it depends
how you're crashing. In case of KVM, you can try to cause host crash (example:
echo c > /proc/sysrq-trigger) and see if HA-enabled VMs gets started on a
different host.
- Rohit
<https://cloudstack.apache.org>
________________________________
From: Jon Marshall <jms....@hotmail.co.uk>
Sent: Tuesday, May 22, 2018 8:28:06 PM
To: users@cloudstack.apache.org
Subject: Re: 4.11 without Host-HA framework
Hi Rohit
Thanks for responding.
I have not had much luck with HA at all. I crash a server and nothing
happens in terms of VMs migrating to another host. Monitoring the management
log file it seems the management server recognises the host has stopped
responding to pings but doesn't think it has to do anything.
I am currently running v4.11 with basic network but 3 separate NICs, one
for management, one for storage and one for VMs themselves.
Should it make it any difference ie. would it be worth trying to run
management and storage over the same NIC ?
I am just lost as to why I see no failover at all whereas others are
reporting it works fine.
Jon
________________________________
From: Rohit Yadav <rohit.ya...@shapeblue.com>
Sent: 22 May 2018 12:12
To: users@cloudstack.apache.org
Subject: Re: 4.11 without Host-HA framework
Hi Jon,
Yes, Host-HA is different from VM-HA and without Host HA enabled a HA
enabled VM should be recovered/run on a different host when it crashes.
Historically the term 'HA' in CloudStack is used around high availability of a
VM.
Host HA as the name tries to imply is around HA of a physical hypervisor
host by means of out-of-band management technologies such as ipmi and currently
supporting ipmi as OOBM and KVM hosts with NFS storage.
- Rohit
<https://cloudstack.apache.org>
[https://cloudstack.apache.org/images/monkey-144.png]<https://cloudstack.apache.org/>
Apache CloudStack: Open Source Cloud
Computing<https://cloudstack.apache.org/>
cloudstack.apache.org
CloudStack is open source cloud computing software for creating, managing,
and deploying infrastructure cloud services
________________________________
From: Jon Marshall <jms....@hotmail.co.uk>
Sent: Monday, May 21, 2018 8:36:04 PM
To: users@cloudstack.apache.org
Subject: 4.11 without Host-HA framework
I keep seeing conflicting information about this in the mailing lists and
in blogs etc.
If I run 4.11 without enabling Host HA framework should HA still work if I
crash a compute node because my understanding was the new framework was added
for certain cases only.
It doesn't work for me but I can find a number of people saying you don't
need to enable the new framework for it to work.
Thanks
Jon
rohit.ya...@shapeblue.com
www.shapeblue.com<http://www.shapeblue.com>
53 Chandos Place, Covent Garden, London WC2N 4HSUK @shapeblue
rohit.ya...@shapeblue.com
www.shapeblue.com<http://www.shapeblue.com>
53 Chandos Place, Covent Garden, London WC2N 4HSUK @shapeblue
