Re: [Xen-API] xapi accepting commands before being fully up

[George Dunlap <George.Dunlap@xxxxxxxxxxxxx>]

I'm waiting for ssh to come up because that's the service I plan to use 
next : to ssh onto the host and execute a command; in this case, and xe 
command.
So is the real problem I'm having that I'm logging in over ssh and 
executing the xe command locally, instead of going over the wire?  If I 
were running xe on my "control" box, would it work properly, or would I 
potentially have the same problem?
It looks like I could also make a specific script for XenServer, and add 
an additional step of ssh'ing in and executing "xe event-wait class=host 
name=[hostname] enabled=true" before exiting.   But it just seems 
logical to me that if there's a bunch of initialization to do, you 
should refuse / delay certain classes of queries until after it's done.
Anyway, that's my $0.02, I'll leave it with you guys. :-)
 -George

On 12/07/10 15:43, Anil Madhavapeddy wrote:
> Xapi touches a file when it has finished starting up, based on the 
> -writeinitcomplete command line flag passed to it.  In XenServer, that's 
> defined in the startup script as /var/run/xapi_init_complete.cookie
>
> Might be better to monitor that file, rather than SSH (which is pretty 
> unrelated to xapi, but I'm not sure monitoring 443 would work better as stunnel 
> might come up quite early).
>
> -anil
>
> On 12 Jul 2010, at 15:34, George Dunlap wrote:
>
> > It seems that xapi is up and accepting commands before everything is actually 
> > ready yet.  I have a script that will wait for a host to boot by pinging and 
> > then testing listening on the ssh port; when it succeeds, the host should be up 
> > and ready.
> >
> > However, if I write a command that runs that script, and then immediately tries 
> > to start a VM on that host, I get this error message:
> > ---
> > There are no suitable hosts to start this VM on.
> > The following table provides per-host reasons for why the VM could not be 
> > started:
> >
> > exile    : Cannot start here [Host disabled (use 'xe host-enable' to re-enable)]
> > --
> >
> > Subsequent attempts succeed.
> >
> > It seems like xapi should either wait until all local hosts are up before 
> > accepting vm-start commands, or if they get a command that depends on certain 
> > hosts, it should wait for them to be enabled.
> >
> > I think if that's not easy to do, maybe a "wait-for-host-to-be-initialized" 
> > command... :-)
> >
> > -George
> >
> > _______________________________________________
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> > xen-api@xxxxxxxxxxxxxxxxxxx
> > http://lists.xensource.com/mailman/listinfo/xen-api

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