CODEWITHSUNDEEP
erlangdistributederlang-otp
batman
batman

Reputation: 1447

OTP Distributed Application Takeover

I'm dynamically loading an Erlang application into the system based on a config file which procludes me from starting the distributed app at boot time -- I'm able to get failover to work, but not failback (or in OTP Terms, Takeover.)

Say I have NodeA running the app, and NodeB as a failover node. I pull the cord on NodeA, and the application migrates to NodeB. This is expected. But when I bring NodeA back online and try to call application:start(MyApp) I get:

{error, {shutdown,{myapp, start, [normal,["config.xml"]]}}} Which is indicative of the app failing to start up.

No matter, it fails to start because I have the supervisors running on the other NodeB already, and I've net_adm:ping'ed them together.

I would imagine I can call application:takeover/2 on MyApp to get control back of the node, and kill the application on the other node.

{error,{not_running_distributed, MyApp}}

But this doesn't work either. My Node priority list is [NodeA, {NodeB, NodeC}], so I would think that the app would know to move to the higher priority node once back online.

How do I go about implementing Takeover in this scenario?

Upvotes: 2

Views: 637

Answers (1)

Leo
Leo

Reputation: 121

You may need to use application:takeover/2 instead.

Upvotes: 1

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