Kubernetes multi-container pod [closed] - kubernetes

Question

Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers.
This question does not appear to be about a specific programming problem, a software algorithm, or software tools primarily used by programmers. If you believe the question would be on-topic on another Stack Exchange site, you can leave a comment to explain where the question may be able to be answered.
Closed 4 years ago.
Improve this question
Hello I try to have a Pod with 2 container, one a c++ app, one a mysql database. I used to have the mysql deployed in its own service, but i got latency issue. So i want to try multi-container pod.
But i've been struggling to connect my app with the mysql through localhost. It says..
Can\'t connect to local MySQL server through socket
\'/var/run/mysqld/mysqld.sock
Here is my kubernetes.yaml. Please I need help :(
# Database setup
kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
name: storage-camera
labels:
group: camera
provisioner: kubernetes.io/gce-pd
parameters:
type: pd-ssd
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: camera-pv
labels:
group: camera
spec:
storageClassName: db-camera
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 20Gi
storageClassName: storage-camera
---
# Service setup
apiVersion: v1
kind: Service
metadata:
name: camera-service
labels:
group: camera
spec:
ports:
- port: 50052
targetPort: 50052
selector:
group: camera
tier: service
type: LoadBalancer
---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
name: camera-service
labels:
group: camera
tier: service
spec:
replicas: 1
strategy:
type: RollingUpdate
rollingUpdate:
maxUnavailable: 0
maxSurge: 1
minReadySeconds: 60
template:
metadata:
labels:
group: camera
tier: service
spec:
containers:
- image: asia.gcr.io/test/db-camera:latest
name: db-camera
env:
- name : MYSQL_ROOT_PASSWORD
value : root
ports:
- containerPort: 3306
name: mysql
volumeMounts:
- name: camera-persistent-storage
mountPath: /var/lib/mysql
- name: camera-service
image: asia.gcr.io/test/camera-service:latest
env:
- name : DB_HOST
value : "localhost"
- name : DB_PORT
value : "3306"
- name : DB_NAME
value : "camera"
- name : DB_ROOT_PASS
value : "password"
ports:
- name: http-cam
containerPort: 50052
volumes:
- name: camera-persistent-storage
persistentVolumeClaim:
claimName: camera-pv
restartPolicy: Always

Answer 1

Your MySQL client is configured to use a socket and not talk over the network stack, cf. the MySQL documentation:
On Unix, MySQL programs treat the host name localhost specially, in a
way that is likely different from what you expect compared to other
network-based programs. For connections to localhost, MySQL programs
attempt to connect to the local server by using a Unix socket file.
This occurs even if a --port or -P option is given to specify a port
number. To ensure that the client makes a TCP/IP connection to the
local server, use --host or -h to specify a host name value of
127.0.0.1, or the IP address or name of the local server. You can also specify the connection protocol explicitly, even for localhost, by
using the --protocol=TCP option.
If you still want camera-service to talk over the file system socket you need to mount the file system for the camera-service as well. Currently you only mount it for db-camera