[Ovirt-devel] [PATCH server] Fix race condition with ovirt-identify-node.

[Perry Myers]

Ian Main wrote:
> This patch teaches dbomatic how to keep track of whether or not
> it has actually synced an object with the database.  There were
> problems with db-omatic getting information before the database
> entries were created by ovirt-identify-node and co.  Now dbomatic
> will keep trying until synced with the database.

Ack.  Seems to work for me, I went ahead and pushed this.

Perry

> Signed-off-by: Ian Main <imain at redhat.com>
> ---
>  src/db-omatic/db_omatic.rb |   21 ++++++++++++++++++---
>  1 files changed, 18 insertions(+), 3 deletions(-)
> 
> diff --git a/src/db-omatic/db_omatic.rb b/src/db-omatic/db_omatic.rb
> index ba245e6..fe2d47c 100755
> --- a/src/db-omatic/db_omatic.rb
> +++ b/src/db-omatic/db_omatic.rb
> @@ -29,8 +29,13 @@ class DbOmatic < Qpid::Qmf::Console
>      def update_domain_state(domain, state_override = nil)
>          vm = Vm.find(:first, :conditions => [ "uuid = ?", domain['uuid'] ])
>          if vm == nil
> -          puts "VM Not found in database, must be created by user; ignoring."
> -          return
> +            puts "VM Not found in database, must be created by user; ignoring."
> +
> +            #XXX: I mark this one as 'synced' here even though we couldn't sync
> +            #it because there really should be a db entry for every vm unless it
> +            #was created outside of ovirt.
> +            domain[:synced] = true
> +            return
>          end
>  
>          if state_override != nil
> @@ -61,6 +66,8 @@ class DbOmatic < Qpid::Qmf::Console
>          puts "Updating VM #{domain['name']} to state #{state}"
>          vm.state = state
>          vm.save
> +
> +        domain[:synced] = true
>      end
>  
>      def update_host_state(host_info, state)
> @@ -78,9 +85,15 @@ class DbOmatic < Qpid::Qmf::Console
>              # XXX: This would just be for init..
>              #db_host.is_disabled = 0
>              db_host.save
> +            host_info[:synced] = true
>          else
>              # FIXME: This would be a newly registered host.  We could put it in the database.
>              puts "Unknown host, probably not registered yet??"
> +            # XXX: So it turns out this can happen as there is a race condition on bootup
> +            # where the registration takes longer than libvirt-qpid does to relay information.
> +            # So in this case, we mark this object as not synced so it will get resynced
> +            # again in the heartbeat.
> +            host_info[:synced] = false
>          end
>      end
>  
> @@ -106,6 +119,7 @@ class DbOmatic < Qpid::Qmf::Console
>                  values[:agent_bank] = obj.object_id.agent_bank
>                  values[:class_type] = obj.klass_key[1]
>                  values[:timed_out] = false
> +                values[:synced] = false
>                  puts "New object type #{type}"
>  
>                  new_object = true
> @@ -150,6 +164,7 @@ class DbOmatic < Qpid::Qmf::Console
>                  values[:agent_bank] = obj.object_id.agent_bank
>                  values[:class_type] = obj.klass_key[1]
>                  values[:timed_out] = false
> +                values[:synced] = false
>              end
>              obj.statistics.each do |key, newval|
>                  if values[key.to_s] != newval
> @@ -203,7 +218,7 @@ class DbOmatic < Qpid::Qmf::Console
>                 @cached_objects[objkey][:agent_bank] == agent.agent_bank
>  
>                  values = @cached_objects[objkey]
> -                if values[:timed_out] == true
> +                if values[:timed_out] == true or values[:synced] == false
>                      puts "Marking object of type #{values[:class_type]} as in service."
>                      if values[:class_type] == 'node'
>                          update_host_state(values, Host::STATE_AVAILABLE)


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