Practice Test - Networking Weave

ㅁ How many Nodes are part of this cluster?

(Including master and worker nodes)

$ kubectl get nodes

NAME           STATUS   ROLES    AGE     VERSION
controlplane   Ready    master   3m33s   v1.19.0
node01         Ready    <none>   3m3s    v1.19.0
node02         Ready    <none>   3m4s    v1.19.0
node03         Ready    <none>   3m3s    v1.19.0

ㅁ What is the Networking Solution used by the cluster?

$ ls /etc/cni/net.d

10-weave.conflist

ㅁ How many weave agents/peers are deployed in this cluster?

$ kubectl get pods -n kube-system

NAME                                   READY   STATUS    RESTARTS   AGE
coredns-f9fd979d6-mxmv5                1/1     Running   0          4m54s
coredns-f9fd979d6-pskwm                1/1     Running   1          4m37s
etcd-controlplane                      1/1     Running   0          5m37s
kube-apiserver-controlplane            1/1     Running   0          5m37s
kube-controller-manager-controlplane   1/1     Running   0          5m37s
kube-proxy-gw8h8                       1/1     Running   2          5m18s
kube-proxy-kqj8k                       1/1     Running   2          5m19s
kube-proxy-s7gb5                       1/1     Running   0          5m29s
kube-proxy-t8cp5                       1/1     Running   2          5m18s
kube-scheduler-controlplane            1/1     Running   0          5m37s
weave-net-7qlqp                        2/2     Running   3          4m56s
weave-net-bqrrl                        2/2     Running   3          4m56s
weave-net-l6z8l                        2/2     Running   3          4m55s
weave-net-sr4zh                        2/2     Running   0          4m56s

 

ㅁ On which nodes are the weave peers present?

kubectl get pods -n kube-system -o wide | grep weave

 

ㅁ Identify the name of the bridge network/interface created by weave on eache mode

ip link show

ㅁ What is the POD IP address range configured by weave?

ip address show

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: ens3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 02:42:ac:11:00:0c brd ff:ff:ff:ff:ff:ff
    inet 172.17.0.12/16 brd 172.17.255.255 scope global ens3
       valid_lft forever preferred_lft forever
    inet6 fe80::42:acff:fe11:c/64 scope link 
       valid_lft forever preferred_lft forever
3: docker0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default 
    link/ether 02:42:b3:ac:63:d3 brd ff:ff:ff:ff:ff:ff
    inet 172.18.0.1/24 brd 172.18.0.255 scope global docker0
       valid_lft forever preferred_lft forever
7: datapath: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1376 qdisc noqueue state UNKNOWN group default qlen 1000
    link/ether d6:93:c7:7e:ec:65 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::d493:c7ff:fe7e:ec65/64 scope link 
       valid_lft forever preferred_lft forever
9: weave: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1376 qdisc noqueue state UP group default qlen 1000
    link/ether 2a:77:e6:0a:61:29 brd ff:ff:ff:ff:ff:ff
    inet 10.32.0.1/12 brd 10.47.255.255 scope global weave
       valid_lft forever preferred_lft forever
    inet6 fe80::2877:e6ff:fe0a:6129/64 scope link 
       valid_lft forever preferred_lft forever
11: vethwe-datapath@vethwe-bridge: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1376 qdisc noqueue master datapath state UP group default 
    link/ether 6a:b6:0d:9c:99:b2 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::68b6:dff:fe9c:99b2/64 scope link 
       valid_lft forever preferred_lft forever
12: vethwe-bridge@vethwe-datapath: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1376 qdisc noqueue master weave state UP group default 
    link/ether 9a:3d:c4:97:12:c2 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::983d:c4ff:fe97:12c2/64 scope link 
       valid_lft forever preferred_lft forever
13: vxlan-6784: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 65535 qdisc noqueue master datapath state UNKNOWN group default qlen 1000
    link/ether 8e:0e:c8:32:3b:b9 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::8c0e:c8ff:fe32:3bb9/64 scope link 
       valid_lft forever preferred_lft forever

 

ip adderss show weave

9: weave: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1376 qdisc noqueue state UP group default qlen 1000
    link/ether 2a:77:e6:0a:61:29 brd ff:ff:ff:ff:ff:ff
    inet 10.32.0.1/12 brd 10.47.255.255 scope global weave
       valid_lft forever preferred_lft forever
    inet6 fe80::2877:e6ff:fe0a:6129/64 scope link 
       valid_lft forever preferred_lft forever

 

ㅁ What is the default gateway configured on the PODs scheduled on node03?

 

controlplan에서의 default gateway

ip route

ip route 

default via 172.17.0.1 dev ens3 
10.32.0.0/12 dev weave proto kernel scope link src 10.32.0.1 
10.244.1.0/24 via 172.17.0.40 dev ens3 
10.244.2.0/24 via 172.17.0.42 dev ens3 
10.244.3.0/24 via 172.17.0.21 dev ens3 
172.17.0.0/16 dev ens3 proto kernel scope link src 172.17.0.12 
172.18.0.0/24 dev docker0 proto kernel scope link src 172.18.0.1 linkdown 

node03에서의 ip route

ssh node03 ip route

ssh node03 ip route

default via 172.17.0.1 dev ens3 
10.32.0.0/12 dev weave proto kernel scope link src 10.40.0.0 
10.244.0.0/24 via 172.17.0.12 dev ens3 
10.244.1.0/24 via 172.17.0.40 dev ens3 
10.244.3.0/24 via 172.17.0.21 dev ens3 
172.17.0.0/16 dev ens3 proto kernel scope link src 172.17.0.42 
172.18.0.0/24 dev docker0 proto kernel scope link src 172.18.0.1 linkdown 

[172.17.0.1]

[10.32.0.1]

[10.40.0.0]

[172.18.0.1]

 

실제 IP 할당을 확인하기 위하여 임시 POD를 생성해 본다.

 

$ kubectl run busybox --image=busybox --command sleep 1000 --dry-run=client -o yaml > pod.yaml

vi pod.yaml 에서 spec.nodeName: node03 을 추가한다.

vi pod.yaml

apiVersion: v1
kind: Pod
metadata:
  labels: 
    run: busybox
  name: busybox
spec:
  nodeName: node03
  containers:
  - command:
    - sleep
    - "1000"
    image: busybox
    name: busybox
  

 

busybox pod 생성

 

kubectl apply -f pod.yaml

pod shell에서 직접 ip 확인

 

kubectl exec -ti busybox -- sh 

 

ip r