When I get the logs for one of the pods with the CrashLoopBackOff status
kubectl logs alfred
it returns the following errors.
error: alfred service exiting due to error {"label":"winston","timestamp":"2021-11-08T07:02:02.324Z"} at GetAddrInfoReqWrap.onlookup [as oncomplete] (dns.js:66:26) {
errno: 'ENOTFOUND',
code: 'ENOTFOUND',
syscall: 'getaddrinfo',
hostname: 'mongodb'
} {"label":"winston","timestamp":"2021-11-08T07:02:02.326Z"}error: Client Manager Redis Error: getaddrinfo ENOTFOUND redis {"errno":"ENOTFOUND","code":"ENOTFOUND","syscall":"getaddrinfo","hostname":"redis","stack":"Error: getaddrinfo ENOTFOUND redis\n at GetAddrInfoReqWrap.onlookup [as oncomplete] (dns.js:66:26)","label":"winston","timestamp":"2021-11-08T07:02:02.368Z"}I am new to the Kubernetes and Aws Eks. Would be looking forward to help. Thanks
The errors above were being generated because mongo and redis were not exposed by a service. After I created service.yaml files for the instances the above errors went away. Aws Eks deploys containers in pods which are scattered across different nodes. In order to let mongodb communicate from one pod to another you must expose a service or aka "frontend" for the mongodb deployment.
If you see the error its failing at getaddrinfo, which is a program/function to resolve the dns name and connect with an external service. It is trying to access a redis cluster. Seems like your EKS cluster doesn't have the connectivity.
However if you are running redis as part of your EKS cluster, make sure to provide/update the kubernetes service dns in the application code, or set this as an environment variable which can be set just before deployment.
Its redis and mongodb, also as error says you are providing hostname as redis and mongodb, it won't resolve to an IP address unless you have mapped it in /etc/hosts file which is actually untrue.
Give the correct hostnames, the pods will come up. This is the root-cause.