Von:Barak Azulay <bazulay@redhat.com <mailto:bazulay@redhat.com> <= mailto:bazulay@redhat.com <mailto:bazulay@redhat.com> > >=0D=0A> > > Gese= ndet: Mon 17 November 2014 11:35=0D=0A> > > An: Patrick Lottenbach <pl@a-= bot.ch <mailto:pl@a-bot.ch> <mailto:pl@a-bot.ch <mailto:pl@a-bot.ch> > >= =0D=0A> > > CC: users@ovirt.org <mailto:users@ovirt.org> <mailto:users@o= virt.org <mailto:users@ovirt.org> >=0D=0A> > > Betreff: Re: [ovirt-users]= Fake power management=3F=0D=0A> > >=20=0D=0A> > >=20=0D=0A> > >=20=0D=0A= ----- Original Message -----=0D=0A> > > > From: "mots" <mots@nepu.m= oe <mailto:mots@nepu.moe> <mailto:mots@nepu.moe <mailto:mots@nepu.moe> >= =0D=0A> > > > To: users@ovirt.org <mailto:users@ovirt.org> <mailto:use= rs@ovirt.org <mailto:users@ovirt.org> >=0D=0A> > > > Sent: Friday, Novemb= er 14, 2014 4:54:08 PM=0D=0A> > > > Subject: [ovirt-users] Fake power man= agement=3F=0D=0A> > > >=20=0D=0A> > > > Fake power management=3F Hello,=0D= =0A> > > >=20=0D=0A> > > > I'm building a small demonstration system for = our sales team to take to a=0D=0A> > > > customer so that they can show t= hem our solutions.=0D=0A> > > > Hardware: Two Intel NUC's, a 4 port switc= h and a laptop.=0D=0A> > > > Engine: Runs as a VM on one of the NUCs, whi= ch one it runs on is=0D=0A> > > > determined=0D=0A> > > > by pacemaker.=0D= =0A> > > > Storage: Also managed by pacemaker, it's drbd backed and acces= sed with=0D=0A> > > > iscsi.=0D=0A> > > > oVirt version: 3.5=0D=0A> > > >= OS: CentOS 6.6=0D=0A> > > >=20=0D=0A> > > > The idea is to have our sale= s representative (or the potential customer=0D=0A> > > > himself) randoml= y pull the plug on one of the NUCs to show that the=0D=0A> > > > system=0D= =0A> > > > stays operational when part of the hardware fails.=0D=0A> > >=20= =0D=0A> > > I assume you are aware that the engine might fence the node i= t is running=0D=0A> > > on ...=0D=0A> > > Or do you use pacemaker to run =
------=_Part_39_1687046635.1416266377877 Content-Type: multipart/alternative; boundary="=_t8EqHT3xdZg+XwUZZBd4cSFdl9lEQF49Im0BRY50j2FqCbqe" This is a multi-part message in MIME format. Your mail reader does not understand MIME message format. --=_t8EqHT3xdZg+XwUZZBd4cSFdl9lEQF49Im0BRY50j2FqCbqe Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable -----Urspr=C3=BCngliche Nachricht-----=0D=0A=0D=0A> Von:Barak Azulay <baz= ulay@redhat.com <mailto:bazulay@redhat.com> >=0D=0A> Gesendet: Mon 17 Nov= ember 2014 23:30=0D=0A> An: Patrick Lottenbach <pl@a-bot.ch <mailto:pl@a-= bot.ch> >=0D=0A> CC: users@ovirt.org <mailto:users@ovirt.org>=20=0D=0A> B= etreff: Re: AW: [ovirt-users] Fake power management=3F=0D=0A>=20=0D=0A> W= ell you can hack the solution in the form of replacing the fencing master= script to always return success (Eli can help you with that),=0D=0A> and= define an imaginary fencing device on each host ... meaning that the fen= cing command will always succeeds.=0D=0A>=20=0D=0A=0D=0AThis sounds inter= esting. It's exactly what I need.=0D=0A=0D=0A> But this may be risky ... = as you might end up with the same VM running on 2 hosts.=20=0D=0A=0D=0AAs= I see it, this would only happen if someone unplugs the network interfac= e. I know this is a way to break the cluster. If someone unplugs the inte= rface, then everything gets started twice anyways thanks to pacemaker bei= ng configured to ignore the lack of quorum and it would look silly in fro= nt of the customer.=0D=0A=0D=0A> And one last note ... when you disconnec= t one of the hosts in the demo you mentioned, I think you'll be better to= disconnect the host that does not run the engine ...=0D=0A=20=0D=0AIt ju= st gets restarted on the remaining node and resumes operation. It even re= members which guests ran on which host.=0D=0AThat part is really safe. Th= e storage is configured to only report data as written when the write ope= ration has finished on all (currently online) nodes, disk write caches ar= e turned off in lvm.conf. PostreSQL is resilient enough to survive a cras= h like this.=0D=0A=0D=0AOr am I missing something that might break=3F=0D=0A= =0D=0A> Barak=20=0D=0A=0D=0Amots=0D=0A=0D=0A>=20=0D=0A> ----- Original Me= ssage -----=0D=0A> > From: "mots" <mots@nepu.moe <mailto:mots@nepu.moe> >= =0D=0A> > To: "Barak Azulay" <bazulay@redhat.com <mailto:bazulay@redhat.c= om> >=0D=0A> > Cc: users@ovirt.org <mailto:users@ovirt.org>=20=0D=0A> > S= ent: Monday, November 17, 2014 12:58:20 PM=0D=0A> > Subject: AW: [ovirt-u= sers] Fake power management=3F=0D=0A> >=20=0D=0A> > Yes, pacemaker manage= s the engine. That part is working fine, the engine=0D=0A> > restarts on = the remaining node without problems.=0D=0A> > It's just that the guests d= on't come back up until the powered down node has=0D=0A> > been fenced ma= nually.=0D=0A> >=20=0D=0A> > -----Urspr=C3=BCngliche Nachricht-----=0D=0A= the engine as well =3F=0D=0A> > >=20=0D=0A> > > > My problem is that I do= n't have any way to implement power management, so=0D=0A> > > > the=0D=0A=
Engine can't fence nodes and won't restart guests that were runni= ng on=0D=0A> > > > the=0D=0A> > > > node which lost power. In pacemaker I= can just configure fencing over SSH=0D=0A> > > > or=0D=0A> > > > even di= sable the requirement to do so completely. Is there something=0D=0A> > > = similar=0D=0A> > > > for oVirt, so that the Engine will consider a node= which it can't connect=0D=0A> > > > to=0D=0A> > > > to be powered down=3F= =0D=0A> > > >=20=0D=0A> > > > Regards,=0D=0A> > > >=20=0D=0A> > > > mots=0D= =0A> > > >=20=0D=0A> > > > ______________________________________________= _=0D=0A> > > > Users mailing list=0D=0A> > > > Users@ovirt.org <mailto:Us= ers@ovirt.org> <mailto:Users@ovirt.org <mailto:Users@ovirt.org> >=0D=0A>= http://lists.ovirt.org/mailman/listinfo/users <http://lists.ovirt.= org/mailman/listinfo/users>=20=0D=0A> > > > <" target=3D"_blank">http://l= ists.ovirt.org/mailman/listinfo/users> <http://lists.ovirt.org/mailman/li= stinfo/users> ;=0D=0A> > > >=20=0D=0A> > >=20=0D=0A> >=20=0D=0A> >=0D=0A>= =20=0D=0A=0D=0A --=_t8EqHT3xdZg+XwUZZBd4cSFdl9lEQF49Im0BRY50j2FqCbqe Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: quoted-printable
> But this may be risky ... as you might end up with the same VM runn= ing on 2 hosts. <br><br>As I see it, this would only happen if someone un=
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://ww= w.w3.org/TR/html4/loose.dtd"><html>=0A<head>=0A <meta name=3D"Generator"= content=3D"Zarafa WebApp v7.1.10-44973">=0A <meta http-equiv=3D"Content= -Type" content=3D"text/html; charset=3Dutf-8">=0A <title>AW: [ovirt-user= s] Fake power management=3F</title>=0A</head>=0A<body>=0A-----Urspr=C3=BC= ngliche Nachricht-----<br><pre style=3D"white-space: -moz-pre-wrap; white= -space: -pre-wrap; white-space: -o-pre-wrap; white-space: pre-wrap; word-= wrap: break-word;" wrap=3D"">> Von:Barak Azulay <<a href=3D"mailto:= bazulay@redhat.com">bazulay@redhat.com</a>><br>> Gesendet: Mon 17 N= ovember 2014 23:30<br>> An: Patrick Lottenbach <<a href=3D"mailto:p= l@a-bot.ch">pl@a-bot.ch</a>><br>> CC: <a href=3D"mailto:users@ovirt= =2Eorg">users@ovirt.org</a><br>> Betreff: Re: AW: [ovirt-users] Fake p= ower management=3F<br>> <br>> Well you can hack the solution in the= form of replacing the fencing master script to always return success (El= i can help you with that),<br>> and define an imaginary fencing device= on each host ... meaning that the fencing command will always succeeds.<= br>> <br><br>This sounds interesting. It's exactly what I need.<br><br= plugs the network interface. I know this is a way to break the cluster. I= f someone unplugs the interface, then everything gets started twice anywa= ys thanks to pacemaker being configured to ignore the lack of quorum and = it would look silly in front of the customer.<br><br>> And one last no= te ... when you disconnect one of the hosts in the demo you mentioned, I = think you'll be better to disconnect the host that does not run the engin= e ...<br> <br>It just gets restarted on the remaining node and resumes op= eration. It even remembers which guests ran on which host.<br>That part i= s really safe. The storage is configured to only report data as written w= hen the write operation has finished on all (currently online) nodes, dis= k write caches are turned off in lvm.conf. PostreSQL is resilient enough = to survive a crash like this.<br><br>Or am I missing something that might= break=3F<br><br>> Barak <br><br>mots<br><br>> <br>> ----- Origi= nal Message -----<br>> > From: "mots" <<a href=3D"mailto:mots@ne= pu.moe">mots@nepu.moe</a>><br>> > To: "Barak Azulay" <<a href= =3D"mailto:bazulay@redhat.com">bazulay@redhat.com</a>><br>> > Cc= : <a href=3D"mailto:users@ovirt.org">users@ovirt.org</a><br>> > Sen= t: Monday, November 17, 2014 12:58:20 PM<br>> > Subject: AW: [ovirt= -users] Fake power management=3F<br>> > <br>> > Yes, pacemake= r manages the engine. That part is working fine, the engine<br>> > = restarts on the remaining node without problems.<br>> > It's just t= hat the guests don't come back up until the powered down node has<br>>= > been fenced manually.<br>> > <br>> > -----Urspr=C3=BCng= liche Nachricht-----<br>> > > Von:Barak Azulay <<a href=3D"ma= ilto:bazulay@redhat.com">bazulay@redhat.com</a> <mailto:<a href=3D"mai= lto:bazulay@redhat.com">bazulay@redhat.com</a>> ><br>> > >= Gesendet: Mon 17 November 2014 11:35<br>> > > An: Patrick Lotte= nbach <<a href=3D"mailto:pl@a-bot.ch">pl@a-bot.ch</a> <mailto:<a hr= ef=3D"mailto:pl@a-bot.ch">pl@a-bot.ch</a>> ><br>> > > CC: = <a href=3D"mailto:users@ovirt.org">users@ovirt.org</a> <mailto:<a href= =3D"mailto:users@ovirt.org">users@ovirt.org</a>><br>> > > Bet= reff: Re: [ovirt-users] Fake power management=3F<br>> > > <br>&g= t; > > <br>> > > <br>> > > ----- Original Message= -----<br>> > > > From: "mots" <<a href=3D"mailto:mots@nep= u.moe">mots@nepu.moe</a> <mailto:<a href=3D"mailto:mots@nepu.moe">mots= @nepu.moe</a>> ><br>> > > > To: <a href=3D"mailto:users= @ovirt.org">users@ovirt.org</a> <mailto:<a href=3D"mailto:users@ovirt.= org">users@ovirt.org</a>><br>> > > > Sent: Friday, Novembe= r 14, 2014 4:54:08 PM<br>> > > > Subject: [ovirt-users] Fake = power management=3F<br>> > > > <br>> > > > Fake p= ower management=3F Hello,<br>> > > > <br>> > > > = I'm building a small demonstration system for our sales team to take to a= <br>> > > > customer so that they can show them our solutions= =2E<br>> > > > Hardware: Two Intel NUC's, a 4 port switch and= a laptop.<br>> > > > Engine: Runs as a VM on one of the NUCs= , which one it runs on is<br>> > > > determined<br>> > = > > by pacemaker.<br>> > > > Storage: Also managed by p= acemaker, it's drbd backed and accessed with<br>> > > > iscsi= =2E<br>> > > > oVirt version: 3.5<br>> > > > OS: = CentOS 6.6<br>> > > > <br>> > > > The idea is to = have our sales representative (or the potential customer<br>> > >= ; > himself) randomly pull the plug on one of the NUCs to show that th= e<br>> > > > system<br>> > > > stays operational = when part of the hardware fails.<br>> > > <br>> > > I a= ssume you are aware that the engine might fence the node it is running<br=
> > > on ...<br>> > > Or do you use pacemaker to run t= he engine as well =3F<br>> > > <br>> > > > My proble= m is that I don't have any way to implement power management, so<br>> = > > > the<br>> > > > Engine can't fence nodes and wo= n't restart guests that were running on<br>> > > > the<br>>= ; > > > node which lost power. In pacemaker I can just configure= fencing over SSH<br>> > > > or<br>> > > > even d= isable the requirement to do so completely. Is there something<br>> &g= t; > > similar<br>> > > > for oVirt, so that the Engine= will consider a node which it can't connect<br>> > > > to<br= > > > > to be powered down=3F<br>> > > > <br>>= ; > > > Regards,<br>> > > > <br>> > > > = mots<br>> > > > <br>> > > > _____________________= __________________________<br>> > > > Users mailing list<br>&= gt; > > > <a href=3D"mailto:Users@ovirt.org">Users@ovirt.org</a>= <mailto:<a href=3D"mailto:Users@ovirt.org">Users@ovirt.org</a>><br= > > > > <a href=3D"http://lists.ovirt.org/mailman/listinfo/u= sers" target=3D"_blank">http://lists.ovirt.org/mailman/listinfo/users</a>= <br>> > > > <<a href=3D"http://lists.ovirt.org/mailman/lis= tinfo/users>" target=3D"_blank">http://lists.ovirt.org/mailman/listinfo/u= sers></a>;<br>> > > > <br>> > > <br>> > <br= > ><br>> </pre>=0A</body>=0A</html> --=_t8EqHT3xdZg+XwUZZBd4cSFdl9lEQF49Im0BRY50j2FqCbqe--
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