[slurm-users] Internet connection loss with srun to a node

[Mahmood Naderan]

I thought that maybe srun doesn't transfer all settings from the head node
to the compute node.
The wget command works on frontend but doesn't work on the compute.

mahmood at main-proxy:~$ wget google.com
--2020-08-02 16:05:55--  http://google.com/
Resolving google.com (google.com)... 216.58.215.238,
2a00:1450:400a:800::200e
Connecting to google.com (google.com)|216.58.215.238|:80... connected.
HTTP request sent, awaiting response... 301 Moved Permanently
Location: http://www.google.com/ [following]
--2020-08-02 16:05:55--  http://www.google.com/
Resolving www.google.com (www.google.com)... 172.217.168.68,
2a00:1450:400a:803::2004
Connecting to www.google.com (www.google.com)|172.217.168.68|:80...
connected.
HTTP request sent, awaiting response... 200 OK
Length: unspecified [text/html]
Saving to: ‘index.html’

index.html                         [ <=>
            ]  12.68K  --.-KB/s    in 0s

2020-08-02 16:05:56 (196 MB/s) - ‘index.html’ saved [12983]

mahmood at main-proxy:~$ srun -p gpu_part --gres=gpu:titanv:1  --pty /bin/bash
mahmood at fry0:~$ wget google.com
--2020-08-02 16:05:30--  http://google.com/
Resolving google.com (google.com)... 216.58.215.238,
2a00:1450:400a:800::200e
Connecting to google.com (google.com)|216.58.215.238|:80... ^C
mahmood at fry0:~$




I will check the gateway with the admin.
Thanks for the hint.



Regards,
Mahmood




On Sun, Aug 2, 2020 at 5:58 PM Renfro, Michael <Renfro at tntech.edu> wrote:

> Probably unrelated to slurm entirely, and most likely has to do with
> lower-level network diagnostics. I can guarantee that it’s possible to
> access Internet resources from a compute node. Notes and things to check:
>
> 1. Both ping and http/https are IP protocols, but are very different (ping
> isn’t even TCP or UDP, it’s ICMP), so even if you needed proxy variables
> for http and https to work, they shouldn’t affect ping.
>
> 2. Do http or https transfers work from a compute node? A github clone, a
> test with curl or wget to a nearby web server? Do your proxy variables
> exist on the compute node, and most importantly, is there a proxy server
> listening and functional on the host and port that the variables point to?
>
> 3. What’s the default gateway for your compute nodes? Does that gateway
> provide network address translation (NAT) for the nodes, or does it work as
> a traditional router?
>
> Get Outlook for iOS <https://aka.ms/o0ukef>
> ------------------------------
> *From:* slurm-users <slurm-users-bounces at lists.schedmd.com> on behalf of
> Mahmood Naderan <mahmood.nt at gmail.com>
> *Sent:* Sunday, August 2, 2020 7:52:52 AM
> *To:* Slurm User Community List <slurm-users at lists.schedmd.com>
> *Subject:* [slurm-users] Internet connection loss with srun to a node
>  Hi
> A frontend machine is connected to the internet and from that machine, I
> use srun to get a bash on another node. But it seems that the node is
> unable to access the internet. The http_proxy and https_proxy are defined
> in ~/.bashrc
>
> mahmood at main-proxy:~$ ping google.com
> PING google.com (216.58.215.238) 56(84) bytes of data.
> 64 bytes from zrh11s02-in-f14.1e100.net (216.58.215.238): icmp_seq=1
> ttl=114 time=1.38 ms
> ^C
> --- google.com ping statistics ---
> 1 packets transmitted, 1 received, 0% packet loss, time 0ms
> rtt min/avg/max/mdev = 1.384/1.384/1.384/0.000 ms
> mahmood at main-proxy:~$ srun -p gpu_part --gres=gpu:titanv:1  --pty
> /bin/bash
> mahmood  @fry0:~$ ping google.com
> PING google.com (216.58.215.238) 56(84) bytes of data.
> ^C
> --- google.com ping statistics ---
> 3 packets transmitted, 0 received, 100% packet loss, time 2026ms
>
>
>
> I guess that is related to slurm and srun.
> Any idea for that?
>
>
>
>
>
>
>
> Regards,
> Mahmood
>
>
>
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