CODEWITHSUNDEEP
kubernetesopenshift
Rakesh Kotian
Rakesh Kotian

Reputation: 167

Pod unable to install packages(apt-get update or apt-get install )

I have observed that the pods in my cluster is not able to install the packages when exec to the pod . While debugging i have realized that its due to /etc/resolv.conf entries.

The /etc/resolv.conf entry from one of the pod is :

nameserver 192.168.27.116
search ui-container.svc.cluster.local svc.cluster.local cluster.local 192.168.27.116.nip.io
options ndots:5

Here if i remove a entry 192.168.27.116.nip.io from the resolv.conf of all the master, worker nodes then the pods will be able to connect to internet and apt-get update and apt-get install works. This is only a temporary workaround because it is not recommended to update the resolv.conf. because i have observed that resolv.conf contents gets re-set to original upon reboot of the nodes.

Is it due to options ndots:5 in the /etc/resolv.conf ?

How can i fix this?

Upvotes: 6

Views: 4868

Answers (3)

user2039152
user2039152

Reputation: 146

Adding to above answers, usually resolve.conf follows following pattern

nameserver <local domain server provided by docker>
search <pod namespace>.svc.cluster.local svc.cluster.local cluster.local <host/node's actual DNS>
options ndots:5

Last part of the DNS <host/node's actual DNS> is usually your LAB's or system wide DNS that is part of your network. So you may have override with DNS policy or update the same in your lab. nip.io is a FQDN maker where there is a need, so you may come up with a local DNS name that resolves within your LAB instead of relying on that.

Upvotes: 2

Ottovsky
Ottovsky

Reputation: 2258

As a quick-fix, you could leverage dnsConfig from pod Spec to override default dns configuration, more details: https://kubernetes.io/docs/concepts/services-networking/dns-pod-service/#pod-dns-config

Upvotes: 4

Gustavo Kawamoto
Gustavo Kawamoto

Reputation: 3077

No, it's because of the nip.io address in your resolv.conf. It's a special domain that's used for reflection and mocking. It's not the ndots:5.

Upvotes: 3

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