Let's take a look at a slightly modified version of the go-demo-2 definition:
cat res/go-demo-2-insuf-mem.yml
When compared with the previous definition, the difference is only in resources of the db container in the go-demo-2-db Deployment.
The output, limited to the relevant parts, is as follows:
apiVersion: apps/v1beta2
kind: Deployment
metadata:
name: go-demo-2-db
spec:
...
template:
...
spec:
containers:
- name: db
image: mongo:3.3
resources:
limits:
memory: 10Mi
cpu: 0.5
requests:
memory: 5Mi
cpu: 0.3
The memory limit is set to 10Mi and the request to 5Mi. Since we already know from Heapster's data that MongoDB requires around 38Mi, memory resources...