6. Docker Coins en Kubernetes¶
En este laboratorio montara la conocida aplicacion Docker Coins en Kubernetes, especificamente se clono este repositorio Docker Coins
Cada microservicio(worker,rng,webui,hasher) y redis se montara en Pods diferentes.
1. Clonar el repo:
git clone https://github.com/platzi/curso-kubernetes
# dockercoins projects is in dockercoins folder
worker y webui son los unicos microservicios que acceden a otros, se deben modificar las urls de acceso a los otros microservicios, para colocar las urls svc de kubernetes, ya que se usaran servicios NodePort para poder acceder a los microservicios, con los nombres: redis,rng,hasher respectivamente.
### dockercoins/webui/webui.js line 5
- var client = redis.createClient(6379, 'redis');
+ var client = redis.createClient(6379, 'redis.default.svc.cluster.local');
### dockercoins/worker/worker.py line 17
- redis = Redis("redis")
+ redis = Redis("redis.default.svc.cluster.local")
### dockercoins/worker/worker.py line 21
- r = requests.get("http://rng/32")
+ r = requests.get("http://rng.default.svc.cluster.local/32")
### dockercoins/worker/worker.py line 26,27,28
- r = requests.post("http://hasher/",
- data=data,
- headers={"Content-Type": "application/octet-stream"})
+ r = requests.post("http://hasher.default.svc.cluster.local/",
+ data=data,
+ headers={"Content-Type": "application/octet-stream"})
Notar que:
- En nodejs hay que poner la url sin
http://. - En python si hay que colocarlo en las urls que se consumen con la libreria
requests. - La url de
redisno lleva el protocolo:redis.default.svc.cluster.local.
- Crear las imagenes de docker, por facilidad se usara docker-compose para generar todas las imagenes con un comando. Antes apuntar al registry de
minikube - Renombrar las imagenes
docker tag dockercoins_worker santos/docker-coins-worker-app
docker tag dockercoins_hasher santos/docker-coins-hasher-app
docker tag dockercoins_rng:latest santos/docker-coins-rng-app
docker tag dockercoins_webui santos/docker-coins-web-ui-app
kubernetes
config.yaml
apiVersion: v1
kind: ConfigMap
metadata:
name: redis-configmap
namespace: default
data:
redis.conf: |
protected-mode no
maxmemory 32mb
maxmemory-policy allkeys-lru
# cat /usr/local/etc/redis/redis.conf
---
apiVersion: v1
kind: ConfigMap
metadata:
name: redis-sysctl
namespace: default
data:
sysctl.conf: |
net.core.somaxconn=511
vm.overcommit_memory=1
net.core.somaxconn=4096
deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: web-ui
namespace: default
spec:
selector:
matchLabels:
app: web-ui
masterapp: dockercoins
replicas: 1 #
template:
metadata:
labels:
app: web-ui
masterapp: dockercoins
spec:
containers:
- name: web-ui
image: santos/docker-coins-web-ui-app
imagePullPolicy: Never
ports:
- containerPort: 80
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: worker
namespace: default
spec:
selector:
matchLabels:
app: worker
masterapp: dockercoins
replicas: 1 #
template:
metadata:
labels:
app: worker
masterapp: dockercoins
spec:
containers:
- name: worker
image: santos/docker-coins-worker-app
imagePullPolicy: Never
# ports:
# - containerPort: 80
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: redis
namespace: default
spec:
selector:
matchLabels:
app: redis
masterapp: dockercoins
replicas: 1 #
template:
metadata:
labels:
app: redis
masterapp: dockercoins
spec:
containers:
- name: redis
image: redis
imagePullPolicy: IfNotPresent
ports:
- containerPort: 6379
volumeMounts:
- mountPath: /usr/local/etc/redis/redis.conf
name: redis-configmap
subPath: redis.conf
- mountPath: /etc/sysctl.conf
name: redis-sysctl
subPath: sysctl.conf
command: ["redis-server", "/usr/local/etc/redis/redis.conf"]
volumes:
- name: redis-configmap
configMap:
name: redis-configmap
- name: redis-sysctl
configMap:
name: redis-sysctl
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: hasher
namespace: default
spec:
selector:
matchLabels:
app: hasher
masterapp: dockercoins
replicas: 1 #
template:
metadata:
labels:
app: hasher
masterapp: dockercoins
spec:
containers:
- name: hasher
image: santos/docker-coins-hasher-app
imagePullPolicy: Never
ports:
- containerPort: 80
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: rng
namespace: default
spec:
selector:
matchLabels:
app: rng
masterapp: dockercoins
replicas: 1 #
template:
metadata:
labels:
app: rng
masterapp: dockercoins
spec:
containers:
- name: rng
image: santos/docker-coins-rng-app
imagePullPolicy: Never
ports:
- containerPort: 80
services.yaml
Notar que en los deployments hay una etiqueta llamada #save as ./services.yaml
apiVersion: v1
kind: Service
metadata:
name: web-ui
namespace: default
spec:
ports:
- port: 80
protocol: TCP
targetPort: 80
selector:
app: web-ui
type: NodePort
---
apiVersion: v1
kind: Service
metadata:
name: redis
namespace: default
spec:
ports:
- port: 6379
# protocol: TCP
targetPort: 6379
selector:
app: redis
type: NodePort
---
apiVersion: v1
kind: Service
metadata:
name: hasher
namespace: default
spec:
ports:
- port: 80
protocol: TCP
targetPort: 80
selector:
app: hasher
type: NodePort
---
apiVersion: v1
kind: Service
metadata:
name: rng
namespace: default
spec:
ports:
- port: 80
protocol: TCP
targetPort: 80
selector:
app: rng
type: NodePort
masterapp con el valor dockercoins, la cual servira para hacer operaciones sobre todos los deployments. 6. Applicar los archivos de configuracion
$ kubectl apply -f config.yaml && kubectl apply -f services.yaml \
&& kubectl apply -f deployment.yaml
# configmap/redis-configmap created
# configmap/redis-sysctl created
# service/web-ui created
# service/redis created
# service/hasher created
# service/rng created
# deployment.apps/web-ui created
# deployment.apps/worker created
# deployment.apps/redis created
# deployment.apps/hasher created
# deployment.apps/rng created
# pod/dnsutils created
# service/web-ui created
# service/redis created
# service/hasher created
# service/rng created
NAME READY STATUS RESTARTS AGE
hasher-6fd7cfd7bf-8v86t 1/1 Running 0 7m51s
redis-594c4d767f-8xfrd 1/1 Running 0 7m51s
rng-648c7c46c7-qrn2m 1/1 Running 0 7m51s
web-ui-57b7674785-7cfj2 1/1 Running 0 7m51s
worker-67ff756f89-wvmt4 1/1 Running 0 7m51s
1:C 21 Jun 2022 20:47:44.841 # oO0OoO0OoO0Oo Redis is starting oO0OoO0OoO0Oo
1:C 21 Jun 2022 20:47:44.842 # Redis version=7.0.2, bits=64, commit=00000000, modified=0, pid=1, just started
1:C 21 Jun 2022 20:47:44.842 # Configuration loaded
1:M 21 Jun 2022 20:47:44.842 * monotonic clock: POSIX clock_gettime
1:M 21 Jun 2022 20:47:44.843 * Running mode=standalone, port=6379.
1:M 21 Jun 2022 20:47:44.843 # WARNING: The TCP backlog setting of 511 cannot be enforced because /proc/sys/net/core/somaxconn is set to the lower value of 128.
1:M 21 Jun 2022 20:47:44.843 # Server initialized
1:M 21 Jun 2022 20:47:44.843 # WARNING overcommit_memory is set to 0! Background save may fail under low memory condition. To fix this issue add 'vm.overcommit_memory = 1' to /etc/sysctl.conf and then reboot or run the command 'sysctl vm.overcommit_memory=1' for this to take effect.
INFO:__main__:4 units of work done, updating hash counter
INFO:__main__:4 units of work done, updating hash counter
INFO:__main__:4 units of work done, updating hash counter
INFO:__main__:4 units of work done, updating hash counter
INFO:__main__:Coin found: 0c7d1044...
INFO:__main__:4 units of work done, updating hash counter
INFO:__main__:Coin found: 0fe2be6c...
INFO:__main__:4 units of work done, updating hash counter
INFO:__main__:4 units of work done, updating hash counter
INFO:__main__:4 units of work done, updating hash counter
172.17.0.1 - - [21/Jun/2022:20:51:50 +0000] "POST / HTTP/1.1" 200 64 0.1007
172.17.0.1 - - [21/Jun/2022:20:51:50 +0000] "POST / HTTP/1.1" 200 64 0.1008
172.17.0.1 - - [21/Jun/2022:20:51:50 +0000] "POST / HTTP/1.1" 200 64 0.1006
172.17.0.1 - - [21/Jun/2022:20:51:50 +0000] "POST / HTTP/1.1" 200 64 0.1007
172.17.0.1 - - [21/Jun/2022:20:51:51 +0000] "POST / HTTP/1.1" 200 64 0.1007
172.17.0.1 - - [21/Jun/2022 20:52:03] "GET /32 HTTP/1.1" 200 -
172.17.0.1 - - [21/Jun/2022 20:52:03] "GET /32 HTTP/1.1" 200 -
172.17.0.1 - - [21/Jun/2022 20:52:03] "GET /32 HTTP/1.1" 200 -
172.17.0.1 - - [21/Jun/2022 20:52:04] "GET /32 HTTP/1.1" 200 -
172.17.0.1 - - [21/Jun/2022 20:52:04] "GET /32 HTTP/1.1" 200 -
172.17.0.1 - - [21/Jun/2022 20:52:04] "GET /32 HTTP/1.1" 200 -
WEBUI running on port 80
NodePort de web-ui con minikube
10. Abrir el link en el navegador
Posibles errores¶
- Resolucion de
hostnamessvcen el microservicioworkerowebui, puede ser porque se creo el servicioNodePortde los otros microservicios despues de que se ejecutaran los deplyments, es decir no existian esos hostnames, para esto se puede reiniciar el deployment fallido.
$ kubectl rollout restart deployment worker
# deployment.apps/worker restarted
$ kubectl rollout restart deployment web-ui
# deployment.apps/web-ui restarted
Connection refused o ENOTFOUND, recordar que:
- En nodejs hay que poner la url sin
http://. - En python si hay que colocar el protocolo en las urls que se consumen con la libreria
requests. - La url de
redisno lleva el protocolo:redis.default.svc.cluster.local. ImageNeverPull, no se apunto al registry deminikube:
Mira este lab en Azure Kubernetes Service:¶
En la siguiente pagina podras ver el laboratio link