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Your company has a swarm cluster with 5 manager nodes installed. Unfortunately, at some point three of the managers are down. What will happen to your cluster?

a.All existing service would not accept new sessions but keep the existing one.
b.Every functionality should be working but with decreased performance.
c.Nothing, the cluster should be still fully running.
d.All existing services will go down.
e.The existing services keep running but the scheduler cannot deploy new services or redeploy a failed one.

1 Answer

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Final Answer:

The cluster will e. The existing services keep running but the scheduler cannot deploy new services or redeploy a failed one. (option e)

Step-by-step explanation:

In a Docker Swarm cluster with multiple manager nodes, the loss of three manager nodes would result in a situation where the cluster can still maintain the existing services, but the scheduler would face limitations. Docker Swarm uses a consensus algorithm to make decisions, and with three managers down, the cluster loses quorum, impacting the ability to make certain decisions.

The remaining manager nodes may not have the majority needed for reaching consensus, which affects the scheduling of new services or redeploying failed ones. While existing services can continue to run on the available nodes, the cluster's ability to adapt, scale, or deploy new services is compromised.

This behavior is designed to ensure the stability and consistency of the existing services during partial failures. It prevents unintended consequences and potential conflicts that could arise from attempting to make critical decisions without the required quorum. The Docker Swarm cluster enters a kind of "maintenance mode" where it prioritizes the stability of existing services over introducing new changes.(option e)

User Juvenn Woo
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