The RVGL launcher project has made it even easier to install and play the good old racing game ReVolt.
To play on ubuntu, there are some prereqs you need to have in place, and not all of them are mentioned on the official RVGL launcher. To help you, I have gathered everything in a one liner, just here:
When lauched, you may get an error about a lock file, dont worry, it’s only the first time you run it. Press “Download and Install” in th bottom, and you are ready to play. Remember to explore additional options in the rvgl launcher, it’s packed with cool features š
Gnome NetworkManager is awsome, supporting almost all kinds of VPN solutions, and all you need to do is install a plugin. My main issue is, that my customers often have a pre-build package (for Windows) containing a VPN client including configuration, so they actually dont know how it’s configured.
I usaually figure it out, and then its a breeze to click the network icon, select VPN and activate the connection, this is how it should be on all OS’es.
Unfortunatly there are some minor issues, one of them beeing that if you install the network-manager-vpnc module, you will have the option to create a VPNC based connection, and if you type everything right the first time, it will work. But….
You will not be able to edit the connection, it’s simply not listed when you select VPN settings (Ubuntu 22.04). using nmcli will list the connection, and you will be able to modify it, but I found another soluition, that is much easier.
nm-connection-editor
It will open a small GUI, letting you create, modify or delete all connections.
I have been a very satisfied user of autofs for several years. Using a laptop in multiple location without reboot, could often cause annoying timeouts with hard mounted NFS shares.
So I found autofs, which did a great job, especially the ghost option is nice, making you able to browse the filesystem when it’s not mounted, and only seeing a small delay when the autofs mounts it for you at your wish.
The above options will mount when you try to access the share, and it will unmount after 1 minute of idling, and the _netdev tells the system not to mount it before the network is ready. More or less the same functionality as autofs, but no need to install additional software.
when working with yaml files, indentation is crucial. You can setup vim to make it a little easier, like this:
:set ai ts=2 sw=2 expandtab
The above will set tabstop and shiftwidth to 2 spaces, and make the tab key create spaces instead of tabs. So with this config, you will type 2 spaces, whenever you press tab, just like yaml likes it.
So, you are trying to update your system and get this:
Requesting to save current system state ERROR couldn’t save system state: Minimum free space to take a snapshot and preserve ZFS performance is 20%. Free space on pool “bpool” is xx%
The zfs filesystem is creating a snapshot every time you install a new kernel, this will add up, and suddenly you are not able to update anymore, and you are seeing a lot of error caused by this. If you are unlucky and reboot, it might even brake your system!
Running Ubuntu with zfs will create a pool called bpool as your /boot device. Continuing I will refer to this as bpool.
To get an overview of your zfs pools, use this command: zfspool list
kasper@AsusPro:~$ zpool list NAME SIZE ALLOC FREE CKPOINT EXPANDSZ FRAG CAP DEDUP HEALTH ALTROOT bpool 1.88G 1.64G 238M – – 32% 87% 1.00x ONLINE – rpool 114G 26.3G 87.7G – – 7% 23% 1.00x ONLINE–
As you see, my bpool pool is 87% filled up, I have a problem.
To get an overview of snapshots in the bpool pool, use this command: zfs list -t snapshot | grep bpool
Seems like zfs is not doing any housecleaning by itself, we need to help! To remove a snapshot, we need to destroy it. This is done with the destroy option, like this:
sudo zfs destroy /path/to/snapshot
To remove all snashots in the bpool, you can use the following:
for i in $(zfs list -t snapshot | grep bpool | cut -d ” ” -f 1);do sudo zfs destroy $i; done
This will destroy all snapshots and free up your bpool pool.
If you don’t want to remove all snapshots, pipe your snapshots listing into tail or head. You can add a creation column to the list like this:
zfs list -t snapshot -o name,creation -s creation
This will list your snapshots in order of creation date. Use wc -l to count them and use head to get x amount fewer.
zfs list -t snapshot -o name,creation -s creation | wc -l 20 for i in $(zfs list -t snapshot | grep bpool | cut -d ” ” -f 1 | head -15);do sudo zfs destroy $i; done
I did try to format the commands, but as usual Word Press make things so complicated to use, that i had to revert all the special formatting, instead of spending the entire day figuring out why html tags are not respected in “enlighter inline code”
Adding storage to servers is part of every day work. this can be anything from a virtual disk on a virtual machine, to LUN’s presented from some external storage system.
When the new disk has been added, ususally nothing happens. You need to scan for the new disk/disks in order to operate them. Theres a tool called rescan-scsi-bus.sh for doing this specific task, but sometimes you don’t have that, then you need to do it manually, and it’s actually not that difficult.
You then need to echo “- – -” to the scsi system. I have found a lot of different methods to do the same thing, a lot of them telling you to do something like: echo “- – -” >> /sys/class/scsi_host/hostxx/scan where xx can be anything, and sometimes there’s a lot, so typing all the different host numbers is not optimal. Then someone suggests a for loop, like: for i in $(/sys/class/scsi_host/hosts); do echo “- – -” /sys/class/scsi_host/host$i/scan; done
I have tried them all (I think) but in my opinion, the best and easiest solution is the one below, as it is pretty easy to remember:
echo "- - -" | sudo tee /sys/class/scsi_host/host*/scan
List your newly installed disk with lsblk and partition them with fdisk
The default location for the docker data directory, when using overlay2 storage driver is /var/lib/docker. Maybe you want to move it to another location, and it’s actually pretty easy.
Stop the docker service: sudo systemctl stop docker.service
Copy the docker folder to the new location: sudo cp -rp /var/lib/docker /path/to/new/location The p in -rp will preserve ownership, permissions and timestamps
Tell the docker daemon about the new location by editing the /etc/docker/daemon.json file with the following:
{
"data-root": "/path/to/new/location"
}
4. Start the docker service: sudo systemctl start docker.service
Thats it, the docker directory has been moved.
The above guide is tested on Ubuntu 20.04, but will probably be very much alike on other flavours.
Somehow they missed to get the ssh-copy-id tool implemented, so we need to find another way of copying our ssh keys. Thankfully it’s not that complicated, we can use powershell (probably even cmd)
This will concatenate (cat) your ssh key to the authorized_keys file on your ssh_server.
I’m using cat, to make it easy for Linux/unix admins, type, and get-content will also do, as both cat and type are aliases for get-content. I assume “type” will be available in cmd.exe
/etc/postgresql/12/main/postgresql.conf is where you define the interfaces for postgresql to listen on. It’s done with the line “listen_interfaces =” So, to get postgresql to listen on a docker interface, you have to add the IP address to the configuration:
listen_addresses = 'localhost,172.18.0.1'
This will make postgresql listen after connections from my docker container. Unfortunately when i rebooted the machine, postgresql was only listening on the localhost. That was strange.
After doing some fiddling around, I discovered that I might had a timing issue, and I even found a couple of articles covering the issue. The postgresql service needs to wait for the docker service to be started, or it cannot listen on the docker interface, that seems logical. I tried following some of the workarounds described, but I couldn’t get it to work. I then took a look on how the default systemd is build, and it seems that /etc/systemd/system/default.target.wants/ consist of symbolic links to /lib/systemd/system/whatever, so i did the same:
Using Windows subsystem for Linux (WSL) is so nice, when you are forced to work from an inferior OS, sometimes also referred to as “a gaming console” Especially combined with the Windows Terminal, which I wrote about here: https://www.nordal-lund.dk/?p=592 I’m sure that most Linux/Unix administrators will feel right at home.
Despite all the goodness, there are some minor annoyances preventing me from experiencing a big burst of happiness. One of them are the inability to use ping on a std. WSL Debian as a non-root user. That’s right, you need to do “sudo ping nice.little.address” or you will be denied š
The root cause is the ping utility missing the SUID bit, which it has on the real distro. Luckily there’s an easy fix, add the SUID bit to the ping utility:
sudo chmod u+s /bin/ping
Thats it, now you can ping without sudo again š
