Tue Sep 19

In Go command line flags are processed such that -a=x --a=x -a x --a=x all mean the same thing. The only exception is that booleans true/false cannot be used with the form -a x or --a x.

It turns out that in k8s deployment configs args field (inside container spec) given flags with spaces between name and value does not work (neither would if we wrote this in ["...", ...] style too):

args:
  - --group_conf /dgraph-config/group-mappings
  - --groups "0,1"
  - --idx 1
  - --bindall=true
  - --memory_mb 2048

It turns out in dgraph the --groups flag doesn't require quotes around the arguments so --groups="0,1" can be entered as just --groups=0,1. This point matters because in the k8s deployment spec the former with quotes leads to a parse error in dgraph! This wasted several hours of my time...

apiVersion: apps/v1beta1
kind: Deployment
metadata:
name: dgraph
labels:
  app: dgraph
spec: # ReplicaSet
replicas: 1
template: # Pod
  metadata:
    labels:
      app: dgraph
  spec:
    volumes:
      - name: group-mappings
        configMap:
          name: dgraph-group-mappings.conf
      - name: dgraph
        persistentVolumeClaim:
          claimName: mypvc
    containers:
      - name: dgraph
        image: dgraph/dgraph:latest
        ports:
          - name: ui
            containerPort: 8080
          - name: client
            containerPort: 9080
        command:
          - dgraph
        args:
          - --group_conf=/dgraph-config/group-mappings
          - --groups="0,1"
          - --idx=1
          - --bindall=true
          - --memory_mb=2048
        volumeMounts:
          - name: dgraph
            mountPath: /dgraph
          - name: group-mappings
            mountPath: /dgraph-config

❯ kc logs dgraph-3594762630-2bfm3

Dgraph version : v0.8.1
Commit SHA-1 : 8ea4b0a5
Commit timestamp : 2017-09-18 10:56:37 +1000
Branch : HEAD

2017/09/20 01:39:09 Unable to parse 'groups' configuration