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Deploying Cog on Kubernetes (on AWS)

Note: Use the excellent helm chart - ohaiwalt/cog-helm to get up quickly on k8s

Follow the guide below to understand the inner workings a bit better.

We will be creating 1 deployment for the cog server and 1 deployment for the relay server.

We chose to run Postgres outside the Kubernetes cluster and provide instructions how to expose all service ports on a single ELB.

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Kubectl output options

Let's look at some basic kubectl output options.

Our intention is to list nodes (with their AWS InstanceId) and Pods (sorted by node).

We can start with:

kubectl get no

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$ minikube version
minikube version: v0.14.0

$ minikube start
Starting local Kubernetes cluster...
E0108 18:19:32.625802   27742 start.go:94] Error starting host: Temporary Error: Error configuring auth on host: Too many retries waiting for SSH to be available.  Last error: Maximum number of retries (60) exceeded.

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AWS CLI snippets

The AWS Command Line Interface is a very powerfull ally to anyone managing AWS Infrastructure.

While automating infrastructure with Terraform, some configuration can be quickly retrieved using AWS CLI.

Alternatively, some information is hard to piece together from the AWS console, in which case terminal scripts can provide fast and simple windows into your cloud.

AWS Documentation

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Keybase proof

I hereby claim:

• I am so0k on github.
• I am so0k (https://keybase.io/so0k) on keybase.
• I have a public key ASDaffdVrhOLCfx0kMlQsvx-HA8ygWIhW3IpSrvYEFVP6Qo

To claim this, I am signing this object:

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Getting an Alpine shell

Often usefull for in-cluster debugging.

$ kubectl run --generator=run-pod/v1 --image=alpine:3.5 -it alpine-shell -- /bin/sh

detach (without killing the container):

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Use netcat to wait until port 8080 is open

while ! nc -z localhost 8080; do sleep 0.1; done; echo test

in a separate session open port 8080 (using netcat):

nc -l 8080

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import yaml

print_format="| {parameter:<40}| | {default:<50}|"
def walk_dict(d,keys=[],depth=0):
    for k,v in sorted(d.items(),key=lambda x: x[0]):
        keys.append(k)
        if isinstance(v,dict):
            walk_dict(v,keys,depth+1)
        else:
            print(print_format.format(parameter='`{0}`'.format(".".join(keys)),default='`{0}`'.format(v)))

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Play with Moby - Docker Singapore - June 2017

• Driven by yaml file which defines the assembly we want to create:

  1. kernel (to build bootable vm, stored under /boot) ~> see kernel files info should point to container image which has kernel file (i.e. bzImage) and tar with kernel modules
  2. init: list of images used for init system (unpacked into root filesystem). In case of LinuxKit system this should bring up containerd and system containers

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PSQL

Magic words:

psql -U postgres

If run with -E flag, it will describe the underlaying queries of the \ commands (cool for learning!).

Most \d commands support additional param of __schema__.name__ and accept wildcards like *.*