I created a Pod (see config below) on k8s (AKS, k8s version 1.19.7) with cpu="6" and memory=20G. So I expected the Pod to have 6 cores on the CPU as I read on the k8s docu
One cpu, in Kubernetes, is equivalent to 1 vCPU/Core for cloud providers
When I check lscpu on the container, I get
root@user-ubuntu:/# lscpu
Architecture: x86_64
CPU op-mode(s): 32-bit, 64-bit
Byte Order: Little Endian
Address sizes: 46 bits physical, 48 bits virtual
CPU(s): 16 <-- 2x 8 hyperthreading cores?
On-line CPU(s) list: 0-15
Thread(s) per core: 2
Core(s) per socket: 8 <-- expected 6
Socket(s): 1
NUMA node(s): 1
Vendor ID: GenuineIntel
CPU family: 6
Model: 85
Model name: Intel(R) Xeon(R) Platinum 8168 CPU @ 2.70GHz Also, the memory seems to be 32G instead of 20G
root@user-ubuntu:/# vmstat -s -S M
32114 M total memorykind: Pod
apiVersion: v1
metadata:
name: user-ubuntu
spec:
containers:
- name: user-ubuntu
image: ubuntu:latest
command: ["/bin/sleep", "3650d"]
imagePullPolicy: IfNotPresent
resources:
requests:
cpu: "6"
memory: 20G
limits:
cpu: "6"
memory: 20G
volumeMounts:
- mountPath: "/mnt/azure"
name: volume
restartPolicy: Always
volumes:
- name: volume
persistentVolumeClaim:
claimName: pvc-user-defaultThe lscpu command displays kernel resoures, in particular, from /proc/cpuinfo (see documentation). Now, all the containers running on host system (which can be a physical machine or a VM) share the same kernel (this is the distinguishing feature of containers vs. VMs). Thus, the information you get from lscpu corresponds to the underlying host and not the container.
Here's a list of references where this issue is discussed:
Your container is however restricted by a cgroup to the resource usage you defined in the Pod definition. So, even though lscpu displays 16 cores, your container can still only use 6 of them. The same applies for the memory.