Kubernetes/Networking
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Networking in Kubernetes is using Linux Network namespace. Each Pod has IP address assosiated with it. It recives this IP from Virtual Ethernet interface pair.
#Find out node that 'nginx' pod is running on
kubectl -n default get pods -owide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
nginx-7cdbd8cdc9-89zcf 1/1 Running 1 8d 10.100.2.7 worker-2.acme.com <none> <none>
# Ssh to worker-2.acme.com
user@worker-2:~$ ifconfig
cni0 Link encap:Ethernet HWaddr fe:70:ee:29:26:ca
inet addr:10.100.2.1 Bcast:0.0.0.0 Mask:255.255.255.0
inet6 addr: fe80::fc70:eeff:fe29:26ca/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:8951 Metric:1
RX packets:2 errors:0 dropped:0 overruns:0 frame:0
TX packets:56 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:56 (56.0 B) TX bytes:6576 (6.5 KB)
docker0 Link encap:Ethernet HWaddr 02:42:11:a1:59:d3
inet addr:172.17.0.1 Bcast:172.17.255.255 Mask:255.255.0.0
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
eth0 Link encap:Ethernet HWaddr 02:20:2e:90:a8:66
inet addr:172.31.122.65 Bcast:172.31.127.255 Mask:255.255.240.0
inet6 addr: 2a05:d018:85:e101:2177:162b:63d9:3600/128 Scope:Global
inet6 addr: fe80::20:2eff:fe90:a866/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:9001 Metric:1
RX packets:44256 errors:0 dropped:0 overruns:0 frame:0
TX packets:5078 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:62103701 (62.1 MB) TX bytes:750750 (750.7 KB)
flannel.1 Link encap:Ethernet HWaddr 8a:de:67:53:07:08
inet addr:10.100.2.0 Bcast:0.0.0.0 Mask:255.255.255.255
UP BROADCAST RUNNING MULTICAST MTU:8951 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:18 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:65536 Metric:1
RX packets:231 errors:0 dropped:0 overruns:0 frame:0
TX packets:231 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1
RX bytes:19110 (19.1 KB) TX bytes:19110 (19.1 KB)
veth553fdc8b Link encap:Ethernet HWaddr 12:00:5e:51:c8:92
inet6 addr: fe80::1000:5eff:fe51:c892/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:8951 Metric:1
RX packets:1 errors:0 dropped:0 overruns:0 frame:0
TX packets:82 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:42 (42.0 B) TX bytes:9671 (9.6 KB)
vethef801ebe Link encap:Ethernet HWaddr 92:a8:e7:0e:14:67
inet6 addr: fe80::90a8:e7ff:fe0e:1467/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:8951 Metric:1
RX packets:1 errors:0 dropped:0 overruns:0 frame:0
TX packets:76 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:42 (42.0 B) TX bytes:9216 (9.2 KB)
# See containers running on this node
sudo docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
fddffd510a62 nginx "nginx -g '14 minu Up 14 k8s_nginx_nginx-7cdbd8cdc9-89zcf_default_9c89e271-a07c-11e9-80e8-02f78428aaf6_1
16509cc4326d k8s.gcr.io/pause:3.1 "/pause" 14 minu Up 14 k8s_POD_nginx-7cdbd8cdc9-89zcf_default_9c89e271-a07c-11e9-80e8-02f78428aaf6_4
continue @1.46