question Re: HiveServer not starting on docker image of apache ambari. Getting Couldn't resolve host error. in Archives of Support Questions (Read Only)

HiveServer not starting on docker image of apache ambari. Getting Couldn't resolve host error.

amit_kumar — Sun, 18 Aug 2019 12:25:07 GMT

Hi,

While starting Hiveserver2 in apache ambari, I'm getting "Couldn't resolve host" issue.

My ambari setup is a docker image having 3 clusters.

I can see that, as part to resolve the host it is taking the docker container name followed by the port no. I completely doubt if that is going to work.

http://16aadcc9c315:50070 not sure why it is like this.

16aadcc9c315 is the name of one of my cluster which is a docker image.

Any input on this will be appreciable?

Below is the error in logs file:

Re: HiveServer not starting on docker image of apache ambari. Getting Couldn't resolve host error.

jsensharma — Wed, 01 Feb 2017 15:57:26 GMT

@Amit Kumar

Have you configured the FQDN properly for all your hosts and are they able to access each other using the FQDN?

Following command should show the hostname it should use.

hostname -f

Please see the following link to know why correct FQDN configuration is needed for communication and how to edit the "/etc/hosts"

http://docs.hortonworks.com/HDPDocuments/Ambari-2.2.2.0/bk_Installing_HDP_AMB/content/_check_dns.html

Re: HiveServer not starting on docker image of apache ambari. Getting Couldn't resolve host error.

amit_kumar — Wed, 01 Feb 2017 16:56:49 GMT

Hi,

@Jay SenSharma

Below are the details in /etc/hosts in my 3 clusters.

##################################

127.0.0.1 localhost ::1 localhost ip6-localhost ip6-loopback fe00::0 ip6-localnet ff00::0 ip6-mcastprefix ff02::1 ip6-allnodes ff02::2 ip6-allrouters 172.20.0.2 8c043e0d490c

################################

127.0.0.1 localhost ::1 localhost ip6-localhost ip6-loopback fe00::0 ip6-localnet ff00::0 ip6-mcastprefix ff02::1 ip6-allnodes ff02::2 ip6-allrouters 172.20.0.3 16aadcc9c315

##################################

127.0.0.1 localhost ::1 localhost ip6-localhost ip6-loopback fe00::0 ip6-localnet ff00::0 ip6-mcastprefix ff02::1 ip6-allnodes ff02::2 ip6-allrouters 172.20.0.4 b1ec39e6d58b

#################################

hostname -f shows the name of my container ID for each cluster.

Re: HiveServer not starting on docker image of apache ambari. Getting Couldn't resolve host error.

jsensharma — Wed, 01 Feb 2017 17:03:27 GMT

@Amit Kumar

Do you have the following entries mentioned in all your "/etc/hosts" file

172.20.0.2 8c043e0d490c
172.20.0.3 16aadcc9c315
172.20.0.4 b1ec39e6d58b

After the first two lines of the /etc/hosts file every node of your cluster should have the IP host name mapping. So that they can ping each other using the mentioned hostname. Means each host should be able to access each other with the mentioned hostnames.

Re: HiveServer not starting on docker image of apache ambari. Getting Couldn't resolve host error.

amit_kumar — Wed, 01 Feb 2017 17:11:24 GMT

Hi,

I'm able to ping every node via IP. But with hostname it gives error.

[root@8c043e0d490c /]# ping 16aadcc9c315 ping: unknown host 16aadcc9c315

Thanks!

Re: HiveServer not starting on docker image of apache ambari. Getting Couldn't resolve host error.

jsensharma — Wed, 01 Feb 2017 17:15:27 GMT

@Amit Kumar

Have you already added the follwing 3 lines of entries in *every hosts* "/etc/hosts" file? And then tried Pinging?

172.20.0.2 8c043e0d490c
172.20.0.3 16aadcc9c315
172.20.0.4 b1ec39e6d58b

Re: HiveServer not starting on docker image of apache ambari. Getting Couldn't resolve host error.

amit_kumar — Wed, 01 Feb 2017 17:17:26 GMT

Yes, they are already existing.

Re: HiveServer not starting on docker image of apache ambari. Getting Couldn't resolve host error.

jsensharma — Wed, 01 Feb 2017 17:24:35 GMT

@Amit Kumar

It is good that we have isolated the issue that the hosts are not able to even ping each other means the Host name is not resolvable. That's why you are getting the following error even after addign the /etc/hosts entries.

[root@8c043e0d490c /]# ping 16aadcc9c315 
ping: unknown host 16aadcc9c315

- So it looks like more of a Docker N/W config issue.

- Can you please share more details about how did you configure your docker N/W Settings?

Re: HiveServer not starting on docker image of apache ambari. Getting Couldn't resolve host error.

amit_kumar — Wed, 01 Feb 2017 18:06:41 GMT

It was an ambari image I pulled from docker hub. Did nothing specific to N/W setting for docker. I just turned off my firewall on every node which in turn didn't allow me to ping google.

Re: HiveServer not starting on docker image of apache ambari. Getting Couldn't resolve host error.

amit_kumar — Wed, 01 Feb 2017 18:13:30 GMT

My Bad, I cloned it from github. Below is the link.

https://github.com/weiqingy/caochong

Re: HiveServer not starting on docker image of apache ambari. Getting Couldn't resolve host error.

jsensharma — Wed, 01 Feb 2017 18:48:06 GMT

@Amit Kumar

Not sure if there is anything special in the above mentioned docker instance.

However if you would like to see Ambari's Docker instance / instructions then you might want to look at:

https://cwiki.apache.org/confluence/display/AMBARI/Development+in+Docker

https://github.com/apache/ambari/tree/trunk/dev-support/docker

And

https://github.com/sequenceiq/docker-ambari The above Github repo has more contributors and more Commits. This worked for me many times.

Re: HiveServer not starting on docker image of apache ambari. Getting Couldn't resolve host error.

amit_kumar — Wed, 01 Feb 2017 20:32:37 GMT

So no way to resolve this issue of unknown host name?

Re: HiveServer not starting on docker image of apache ambari. Getting Couldn't resolve host error.

jsensharma — Wed, 01 Feb 2017 20:37:32 GMT

@Amit Kumar It will be more of troubleshooting docker based n/w config. We may need to look from the docker side much... compared to ambari/hive side.

Re: HiveServer not starting on docker image of apache ambari. Getting Couldn't resolve host error.

amit_kumar — Wed, 01 Feb 2017 20:42:14 GMT

Agreed! I'll check for the images provided by you. All thanks!

Re: HiveServer not starting on docker image of apache ambari. Getting Couldn't resolve host error.

amit_kumar — Fri, 03 Feb 2017 13:12:26 GMT

@Jay SenSharma

I was able to fix this by adding the hostname and ip of every cluster in /etc/hosts. I was able to ping after that with the hostname. This worked for me.

All thanks for the input.

Re: HiveServer not starting on docker image of apache ambari. Getting Couldn't resolve host error.

jsensharma — Fri, 03 Feb 2017 13:14:57 GMT

@Amit Kumar

Please accept the answer, if this resolved your issue.

Re: HiveServer not starting on docker image of apache ambari. Getting Couldn't resolve host error.

jsensharma — Fri, 03 Feb 2017 13:37:25 GMT

@Amit Kumar

How did you add the entries in the "/etc/hosts" file something like below ... or in a different way ? AS we already discussed about it .... and i though it did not work for you?

172.20.0.2   8c043e0d490c
172.20.0.3   16aadcc9c315
172.20.0.4   b1ec39e6d58b

Re: HiveServer not starting on docker image of apache ambari. Getting Couldn't resolve host error.

amit_kumar — Fri, 03 Feb 2017 14:35:07 GMT

Yes, it is the same way you mentioned.

I think, I misinterpreted you response and responded wrongly. For each cluster, there were only one entry. I added rest of the two.