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kubectl apply -f pod-app-front.yaml
kubectl get pods
kubectl describe pod openapi-front-pod
kubectl exec -it openapi-front-pod -- /bin/bash
kubectl exec -it openapi-front-pod -- ls /usr/share/nginx/html
for this the cluster have two nodes(node-a and node-b). node-a have two pods: * pod-a have an app angualar * pod-b have an server nginx node-b have the pod-c: * pod-c have on nginx app
creting label to node-a and node-b
kubectl get nodes -o wide
gke-clusterkubernetes-pool-1-19257034-5zl5 Ready <none> 99m v1.14.10-gke.27 10.128.0.8 34.70.33.23 Container-Optimized OS from Google 4.14.138+ docker://18.9.7
gke-clusterkubernetes-pool-1-19257034-nq3r Ready <none> 99m v1.14.10-gke.27 10.128.0.7 35.238.156.105 Container-Optimized OS from Google 4.14.138+ docker://18.9.7
# we apply labels to nodes
kubectl label nodes gke-clusterkubernetes-pool-1-19257034-5zl5 nodename=node-a
kubectl label nodes gke-clusterkubernetes-pool-1-19257034-nq3r nodename=node-b
# we validate labels of the nodes
kubectl get nodes --show-labels
# create pods
kubectl apply -f pods-example/pod-a.yaml
kubectl apply -f pods-example/pod-b.yaml
kubectl apply -f pods-example/pod-c.yaml
# we validate pods creation
kubectl get pods -o wide
pod-a 1/1 Running 0 61s 10.0.1.7 gke-clusterkubernetes-pool-1-19257034-5zl5 <none> <none>
pod-b 0/1 ErrImagePull 0 55s 10.0.1.8 gke-clusterkubernetes-pool-1-19257034-5zl5 <none> <none>
pod-c 0/1 ImagePullBackOff 0 50s 10.0.0.7 gke-clusterkubernetes-pool-1-19257034-nq3r <none> <none># we connect to pod-a
kubectl exec -it pod-a -- sh
# install tool
apt update && apt upgrade && apt install -y curl net-tools traceroute iputils-ping
# get ip
hostname -I
10.0.1.7
# get gateway(10.0.1.1)
route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 10.0.1.1 0.0.0.0 UG 0 0 0 eth0
10.0.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
# we connect to pod-a
kubectl exec -it pod-a -- sh
# install tool
apt update && apt upgrade && apt install -y curl net-tools traceroute iputils-ping
# get ip
hostname -I
10.0.1.9
# get gateway(10.0.1.1)
route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 10.0.1.1 0.0.0.0 UG 0 0 0 eth0
10.0.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
# we connect to pod-c
kubectl exec -it pod-c -- sh
# install tool
apt update && apt upgrade && apt install -y curl net-tools traceroute iputils-ping
# get ip
hostname -I
10.0.0.8
# get gateway(10.0.0.1)
route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 10.0.0.1 0.0.0.0 UG 0 0 0 eth0
10.0.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
it make sense with the result of the command
kubectl get pods -o wide
| node | pod | ip | gateway | |
|---|---|---|---|---|
| node-a | pod-a | 10.0.1.7 | 10.0.1.1 | |
| node-a | pod-b | 10.0.1.9 | 10.0.1.1 | |
| node-b | pod-c | 10.0.0.8 | 10.0.0.1 |
# ping from a to b
ping 10.0.1.9
PING 10.0.1.9 (10.0.1.9) 56(84) bytes of data.
64 bytes from 10.0.1.9: icmp_seq=1 ttl=64 time=0.161 ms
64 bytes from 10.0.1.9: icmp_seq=2 ttl=64 time=0.060 ms
# ping from b to c
ping 10.0.0.8
PING 10.0.0.8 (10.0.0.8) 56(84) bytes of data.
64 bytes from 10.0.0.8: icmp_seq=1 ttl=62 time=1.39 ms
64 bytes from 10.0.0.8: icmp_seq=2 ttl=62 time=0.312 ms
# ping from b to a
ping 10.0.1.7
PING 10.0.1.7 (10.0.1.7) 56(84) bytes of data.
64 bytes from 10.0.1.7: icmp_seq=1 ttl=64 time=0.102 ms
64 bytes from 10.0.1.7: icmp_seq=2 ttl=64 time=0.069 ms
# ping from b to c
ping 10.0.0.8
PING 10.0.0.8 (10.0.0.8) 56(84) bytes of data.
64 bytes from 10.0.0.8: icmp_seq=1 ttl=62 time=1.60 ms
64 bytes from 10.0.0.8: icmp_seq=2 ttl=62 time=0.321 ms
# ping from c to a
ping 10.0.1.7
PING 10.0.1.7 (10.0.1.7) 56(84) bytes of data.
64 bytes from 10.0.1.7: icmp_seq=1 ttl=62 time=1.33 ms
# ping from c to b
# ping 10.0.1.9
PING 10.0.1.9 (10.0.1.9) 56(84) bytes of data.
64 bytes from 10.0.1.9: icmp_seq=1 ttl=62 time=1.39 ms
64 bytes from 10.0.1.9: icmp_seq=2 ttl=62 time=0.340 ms
# ping from c to ip unknow
ping 10.0.1.20
PING 10.0.1.20 (10.0.1.20) 56(84) bytes of data.
From 10.128.0.8 icmp_seq=1 Destination Host Unreachable
From 10.128.0.8 icmp_seq=2 Destination Host Unreachable
if we make one http request from anyone pod to anyone pod the response it will success, the only condition is that port it is open in de container(EXPOSE <port_number>) and the container is listening the request(anyone server)
curl http://10.0.1.7
ok
31385
curl http://10.0.1.9:8080
curl: (7) Failed to connect to 10.0.1.9 port 8080: Connection refused
TODO: hacer un traceroute para demostrar como se comunican los pods y como el cluster crea un router virtual para hacer posible la comunicacion entre diferentes lan
# we connect to pod c
traceroute ip-pod
we will crete 2 pods, in of first pod we going to deploy one application angular as long as that second pod we going to deploy an api rest (django)that contain it services for the angular app.
so that the app is exposed to internet we will have make a service of type nodePort for each app. the angular app wil have exposed the port 30080 while the app django will have exposed the port 30800.
So whit this 2 services we can to acceder both apps(angular app and django admin) but the angular app also it will connect to the api
All yaml files it is into service-nodeport-example folder
# delete all pods
kubectl delete pods pod-a
kubectl delete pods pod-b
kubectl delete pods pod-c
# we create angular and django pods
kubectl apply -f service-nodeport-example/angular-pod.yaml
kubectl apply -f service-nodeport-example/django-pod.yaml
# we validate that the pods they will are created successfully
kubectl get pods -o wide
AME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
angular-pod 1/1 Running 0 2m20s 10.0.1.14 gke-clusterkubernetes-pool-1-19257034-5zl5 <none> <none>
django-pod 1/1 Running 0 2m8s 10.0.0.15 gke-clusterkubernetes-pool-1-19257034-nq3r <none> <none>
# we will create both services
kubectl apply -f service-nodeport-example/angular-nodeport.yaml
kubectl apply -f service-nodeport-example/django-nodeport.yaml
# we will validate that the services they will make created successfully
kubectl get services -o wide
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR
angular-service NodePort 10.64.4.128 <none> 80:30080/TCP 54s app=test,type=frontend
django-service NodePort 10.64.11.21 <none> 8000:30800/TCP 38s app=openapi,type=backend
kubernetes ClusterIP 10.64.0.1 <none> 443/TCP 3d3h <none>
# we can to acceder to angular app throht of the ip of anyone node and the port 30080, for example http://34.70.33.23:30080
kubectl get nodes -o wide
NAME STATUS ROLES AGE VERSION INTERNAL-IP EXTERNAL-IP OS-IMAGE KERNEL-VERSION CONTAINER-RUNTIME
gke-clusterkubernetes-pool-1-19257034-5zl5 Ready <none> 2d11h v1.14.10-gke.27 10.128.0.8 34.70.33.23 Container-Optimized OS from Google 4.14.138+ docker://18.9.7
gke-clusterkubernetes-pool-1-19257034-nq3r Ready <none> 2d11h v1.14.10-gke.27 10.128.0.7 35.238.156.105 Container-Optimized OS from Google 4.14.138+ docker://18.9.7
# also we can acceder to django admin with the ip of the anyone node and the port 30800, for example http://34.70.33.23:30800/admin/
gcloud compute firewall-rules create node-port-service --allow tcp:30080,tcp:30443
gcloud compute instances list NAME ZONE MACHINE_TYPE PREEMPTIBLE INTERNAL_IP EXTERNAL_IP STATUS gke-clusterkubernetes-pool-1-19257034-5zl5 us-central1-c e2-micro 10.128.0.8 34.70.33.23 RUNNING gke-clusterkubernetes-pool-1-19257034-nq3r us-central1-c e2-micro 10.128.0.7 35.238.156.105 RUNNING
curl 34.70.33.23:30080
## pod-d backend api rest
```bash
kubectl apply -f pods-example/pod-d.yaml
kubectl get pods -o wide
kubectl exec -it pod-a -- sh
curl http://10.0.0.10:8000
# desde fuera del cluster intentamos acceder al pod. no disponible
curl http://34.70.33.23:8000
# creamod un sericio nodeport para abrir ese puerto
kubectl apply -f pods-example/node-port-service-backend.yaml
# creamos regla en el firewall
gcloud compute firewall-rules create node-port-service-back --allow tcp:30800
# probamos disponibilidad desde caulquier nodo del cluster.
curl http://34.70.33.23:8000
# conectamos a pod para crear un usuario admin y poder acceder al admin de django
./manage.py createsuperuser
Username: [email protected]
Password:
Password (again):
TODO: modificar app angular para que apunte a la ip del pod backend
kubectl exec -it openapi-front-pod -- sh
apt update && apt upgrade
apt install curl
apt install net-tools
--- routing ip ---
netstat -nr
network services
netstat -pnltu
---- traceroute ---- on pod 2 same node . node 1 : pod-a -> 10.0.0.5, pod-b -> 10.0.0.6(same red lan) -------- node 2: pod c ->
apt install -y net-tools traceroute
traceroute 10.0.0.5
curl 10.0.0.5gcloud container clusters describe clusterkubernetes