Hi, I''m getting bad performance on domUs cause all dom0 and domUs crontab''s are setup at same hour 6,25AM. I want to ask you if there''s something I can use to centralize setup of all crones from domU instead of setting up every domU''s cron (to run in different hours) manually? thanks in advance. -- Regards; Israel Garcia _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Mon, Dec 14, 2009 at 11:30 AM, Israel Garcia <igalvarez@gmail.com> wrote:> Hi, I''m getting bad performance on domUs cause all dom0 and domUs > crontab''s are setup at same hour 6,25AM. I want to ask you if there''s > something I can use to centralize setup of all crones from domU > instead of setting up every domU''s cron (to run in different hours) > manually?I see at least two levels of answering: A) yes, there might be some kind of centralized contrab config tool. This isn''t exclusive to Xen, any datacenter with several similar machines must setup backups and other heavy processes to avoid fighting for some scarce resource (like a fileserver, or a shared device). At the very least, there''s a webmin module for ''cluster cron jobs'' but this might be exactly the opposite (it seems to try to execute all at the same time) B) do you mean running cron in Dom0 instead of on all DomU''s? B.1) on one side it could be reasonable, after all that''s (conceptually) how backup servers do: they have their own scheduler and ''pull'' the data from the running servers. still, i wouldn''t run it in Dom0, but on the machine (virtual or real) that manages the resource. IOW, not a ''cron server'', but a schedule for backups on the backup server, a schedule for updating mirrors on some mirror server, a schedule for OS updates on some local updates mirror, etc. B.2) if you mean having all that''s cron-able managed from Dom0; then no, that''s not how you should do it. First of all, that would mean that this single machine can execute any administration command directly on every machine, creating a HUGE security issue. And second because then you go in a slippery slope of putting everything that''s centralizable on Dom0 (first the cron, then logfiles, oh and logrotate too, the OS updates, why not the users logins, later the SELinux profiles, etc). soon the DomUs are limited to a single process each, and a big, fat Dom0. Much better would be just forget about virtualization, and simply run several processes on a single OS instance. after all, that''s what shared hosting services do -- Javier _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On 12/14/09, Javier Guerra <javier@guerrag.com> wrote:> On Mon, Dec 14, 2009 at 11:30 AM, Israel Garcia <igalvarez@gmail.com> wrote: >> Hi, I''m getting bad performance on domUs cause all dom0 and domUs >> crontab''s are setup at same hour 6,25AM. I want to ask you if there''s >> something I can use to centralize setup of all crones from domU >> instead of setting up every domU''s cron (to run in different hours) >> manually? > > I see at least two levels of answering: > > A) yes, there might be some kind of centralized contrab config tool. > This isn''t exclusive to Xen, any datacenter with several similar > machines must setup backups and other heavy processes to avoid > fighting for some scarce resource (like a fileserver, or a shared > device). At the very least, there''s a webmin module for ''cluster cron > jobs'' but this might be exactly the opposite (it seems to try to > execute all at the same time)\Hi Javier, A) is what I''m looking for...:-) but I don''t like webmin for this job..> > B) do you mean running cron in Dom0 instead of on all DomU''s? > > B.1) on one side it could be reasonable, after all that''s > (conceptually) how backup servers do: they have their own scheduler > and ''pull'' the data from the running servers. still, i wouldn''t run > it in Dom0, but on the machine (virtual or real) that manages the > resource. IOW, not a ''cron server'', but a schedule for backups on the > backup server, a schedule for updating mirrors on some mirror server, > a schedule for OS updates on some local updates mirror, etc. > > B.2) if you mean having all that''s cron-able managed from Dom0; then > no, that''s not how you should do it. First of all, that would mean > that this single machine can execute any administration command > directly on every machine, creating a HUGE security issue. And second > because then you go in a slippery slope of putting everything that''s > centralizable on Dom0 (first the cron, then logfiles, oh and logrotate > too, the OS updates, why not the users logins, later the SELinux > profiles, etc). soon the DomUs are limited to a single process each, > and a big, fat Dom0. Much better would be just forget about > virtualization, and simply run several processes on a single OS > instance. after all, that''s what shared hosting services doI''ll not manage all crontab on a dom0 neither domUs'', maybe from other server.. thanks for your anwer regards, Israel.> > > > -- > Javier >-- Regards; Israel Garcia _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
El lun, 14-12-2009 a las 15:11 -0500, Israel Garcia escribió:> Hi Javier, > > A) is what I''m looking for...:-) but I don''t like webmin for this job.. >You could use any tool for centralized management and configuration like cfengine or puppet to configure crontabs in all your servers. -- Angel L. Mateo Martínez Sección de Telemática Área de Tecnologías de la Información _o) y las Comunicaciones Aplicadas (ATICA) / \\ http://www.um.es/atica _(___V Tfo: 868887590 Fax: 868888337 _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users