On Wed, Dec 9, 2015 at 1:25 AM, George Mamalakis <[email protected]> wrote:
> On 08/12/2015 06:51 μμ, Robert Fisher wrote: > > IMO nothing should ever depend on boot order of nodes. If your > application requires this, its architecture is wrong. If you need A up > before B, that strongly says to me that the application running on B will > die horribly if/when A goes away, even temporarily. I've seen distributed > systems built this way due to devs taking shortcuts and it bit them > horribly further down the line. > > Staggering VM startup, to prevent a "thundering herd" is a different, far > more valid, problem. > > R > > There are situations, like boxes with ldap'ed nswitch mechanisms, where > the LDAP server needs to boot before these boxes in order for them to > acquire the appropriate information and be able to start their services > properly. > What happens if the LDAP server fails after that system is already up and running? Ideally, the system would boot into that same state, which might be online but not functional, and would transition into the functional state when the dependent services become available. Sometimes, as an easier way to implement this, people have a mechanism in the boot process that blocks on availability of such dependent services. Both of those approaches make boot order problem irrelevant. -- Dave ------------------------------------------- smartos-discuss Archives: https://www.listbox.com/member/archive/184463/=now RSS Feed: https://www.listbox.com/member/archive/rss/184463/25769125-55cfbc00 Modify Your Subscription: https://www.listbox.com/member/?member_id=25769125&id_secret=25769125-7688e9fb Powered by Listbox: http://www.listbox.com
