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Re: Canary Node Update

Tyler Schultz
 

Hi Ponraj,

Although it is likely to be the same instance, there is no guarantee that the same instance will be always chosen as the canary. There are many reasons BOSH director would choose a different instance to update first.

You may be interested to know about the `spec.bootstrap` property made available during template rendering. Before making deployment changes BOSH director will select a bootstrap instance and update that instance first. The `spec.bootstrap` property will be true for the given instance. If the bootstrap instance were to go away (eg. scaling the instance count down or switching AZs), director will select a new bootstrap instance.


--Tyler

On Wed, Feb 14, 2018 at 7:59 PM, Ponraj E <ponraj.e@...> wrote:
Hi Colleagues,

Is the canary node chosen by BOSH always the same on every update? Like for example, if we have a three node cluster in a deployment and our update section looks like this:
update:
    canaries: 1
    max_in_flight: 1
 
 i.e., one node at a time. 
 
We see that on every update, the canary node chosen, is always the same. Is there any chance that this behaviour can change, maybe in case, if the canary node is in "stopped" or "failing", will the other VM be picked up for update?
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