getaddrinfo failed: Name or service not known

[gopalakrishna]

 We had face the issue of "getaddrinfo failed: Name or service not known". Today I have try to upgrade "libc6" version upgraded. We have checked libc6 version before upgrading (2.19-0ubuntu6.11). After the libc6 version upgrade process we "rebooted" the instance, but still it's showing the same version libc6(2.19-0ubuntu6.11).

Before upgrading the version,

Distributor ID: Ubuntu
Description: Ubuntu 14.04.1 LTS
Release: 14.04
Codename: trusty

root@test1:~# dpkg -l | grep libc6
ii libc6:amd64 2.19-0ubuntu6.11 amd64 Embedded GNU C Library: Shared libraries
ii libc6-dev:amd64 2.19-0ubuntu6.11 amd64 Embedded GNU C Library: Development Libraries and Header Files

After upgraded the version we rebooted the instance and checked,

root@test1:~# uptime
 05:49:28 up 7 min, 1 user, load average: 0.00, 0.05, 0.05

root@test1:~# dpkg -l | grep libc6
ii libc6:amd64 2.19-0ubuntu6.11 amd64 Embedded GNU C Library: Shared libraries
ii libc6-dev:amd64 2.19-0ubuntu6.11 amd64 Embedded GNU C Library: Development Libraries and Header Files

We again try to upgrade the version, It shows "libc6 is already the newest version".

root@test1:~# apt-get upgrade libc6
Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Done
libc6 is already the newest version.
The following packages have been kept back:
  linux-headers-generic linux-headers-virtual linux-image-virtual
  linux-virtual
0 upgraded, 0 newly installed, 0 to remove and 4 not upgraded.