Category: Work related


Using MESA to render OpenGL > 1.4 remotely

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When you are working on a remote server through nomachine or vnc, and there is no video card on the remote server that supports OpenGL > 1.4, the MESA in default render OpenGL version 1.4. This will cause the application to fail even if they do not really need to raise a GUI. Here is […]

Using Nomachine through ssh tunner

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Nomachine uses port 4000, however, the server may not have that port opened to your local IP. However, as long as you can ssh the server, you can use the following ssh tunnel to use Nomachine – securely and fast: From a ssh client, do: ssh -L <port>:localhost:4000 -N -f <username>@<nomachine_server> From your nomachine client, […]

Scponly cannot chroot

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Scponly from CentOS 7 cannot chroot. Problem is that /sbin/scponlyc does not have corrent SUID. Do a chmod 4755 /sbin/scponlyc resolves it.

Ganglia under php7

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Ganglia web interface cannot display charts in CentOS7, if php is updated to version 7. This is because /usr/share/ganglia/cluster_view.php in line 34, $context_metrics[] was originally initialized as “”, in line 26. If changing line 26 to $context_metrics = []; The problem is fixed.

ssh login slow, stuck on “pledge: exec” if -v

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ssh to a linux box slow after keyed in password, taking 10+ seconds. If using ssh -v, found all the waiting spend on debug info: debug1: pledge: exec This usually happen when something stuck on the systemd-logind service. Restart this service by running systemctl restart systemd-logind usually resolves this without rebooting the box.

When systemctl cannot start/stop services

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This happens when systemd attemps to reload some previously saved state but was not able to. By “kill -1 1” to let it reload itself, systemctl works again without rebooting.

tar gzip a folder with progress bar

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tar cf – folder_name -P | pv -s $(du -sb folder_name | awk ‘{print $1}’) | gzip > folder_zip.tgz

If build cannot find lib

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export LIBRARY_PATH=/path

SSH tunnel

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ssh -f username@remote.host -R <The IP of the interface you want to bind the port>:<port_on_remote_host>:localhost:22 -N Without “The IP of the interface you want to bind the port”, it will only bind on loopback interface 127.0.0.1 To enable binding on other than loopback interface, you have to add GatewayPorts clientspecified in your /etc/ssh/sshd_config and reload […]

AWS: How to mount S3 bucket on your EC2 instance if your role allows it

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s3fs -o iam_role=auto <your_bucket_name> <your_mounting_point>