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Drux
Asked: 2016-07-22 21:32:40 +0800 CST

Attaching to Kubernetes container (for Asterisk) in GKE leads to endless cycle of attach/detach

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I have managed to deploy Asterisk to Google Container Engine (GKE) currently to the extent that a VoIP softphone can register. I'd now like to attach to Asterisk's container.

kubectl attach -it <pod-id>

however leads fast repetitions of Asterisk's CLI prompt (*CLI> *CLI> *CLI ...) without a chance for me to type in anything. It looks as if there is an endless cycle of attach/detach happening. How can I resolve this situation so that I can obtain clean access to the CLI (with a single *CLI> prompt)?

UPDATE The same repetitions happen when to try to attach in two steps:

gcloud compute ssh <instance-id>
<instance># sudo docker attach <image-id>
asterisk voip docker kubernetes google-kubernetes-engine

1 Answers

  1. The cycle of prompts is characteristic of a program which is reading from /dev/null in the belief that it's a tty. The Kubernetes documentation for the stdin field in v1.Container warns about it:

    Whether this container should allocate a buffer for stdin in the container runtime. If this is not set, reads from stdin in the container will always result in EOF. Default is false.

    By the way, the -t flag for kubectl attach does not change whether the container has a tty or not. Except for error messages in some conditions, it's a no-op.

    It seems clear that, as kubectl describe is admitting to you, the asterisk container is being started without stdin and tty. There's no open bug for this. Unless there's a typo (or you're running rktnetes), you might consider opening one for this.

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