Problem:
You’ve uploaded a DEB package to a Launchpad PPA (e.g. using dput), but you get an error message similar to this:
Solution:
You need to use a proper email address (which must be registered in Launchpad) in debian/changelog .
In order to do this, set the $DEBEMAIL environment variable before running dch
Example:
export DEBEMAIL=myemail@example.com dch [...]
If $DEBEMAIL is not set, [username]@[hostname] will be used
You are trying to run a docker container or do the docker tutorial, but you only get an error message like this:
docker: Got permission denied while trying to connect to the Docker daemon socket at unix:///var/run/docker.sock: Post http://%2Fvar%2Frun%2Fdocker.sock/v1.26/containers/create: dial unix /var/run/docker.sock: connect: permission denied. See 'docker run --help'.
The error message tells you that your current user can’t access the docker engine, because you’re lacking permissions to access the unix socket to communicate with the engine.
As a temporary solution, you can use sudo to run the failed command as root.
However it is recommended to fix the issue by adding the current user to the docker group:
Run this command in your favourite shell and then completely log out of your account and log back in (if in doubt, reboot!):
sudo usermod -a -G docker $USER
After doing that, you should be able to run the command without any issues. Run docker run hello-world as a normal user in order to check if it works. Reboot if the issue still persists.
Logging out and logging back in is required because the group change will not have an effect unless your session is closed.
When running smartctl on your hard drive, you often get a plethora of information that can be hard to interpret for unexperienced users. This post attempts to provide aid in interpreting what the technical reasons behind the error messages are. If you’re looking for advice on whether to replace your hard drive, the only guidance I can give you is it might fail any time, so better backup your data, but it might also run for many years to come.. Furthermore, this article does not describe basic SMART WHEN_FAILED checking but rather interpretation of more subtle signs of possibly impending HDD failures.
A few days ago, Let’s Encrypt into public beta. At the time of writing this article, almost 120k certificateshave been issued, including the certificate for TechOverflow.
I really like the Let’s Encrypt service and I believe it might actually change the way people perceive HTTPS encryption. However, there is one rarely-mentioned side-effect when protecting your domains with their certificates.
Let’s Encrypt publishes certificate transparency logs at crt.sh. This transparency does not come without side-effects, however: crt.sh effectively publishes.
In other words, hiding sites from the public by not publishing their (sub-)domain names anywhere will not work when you issue a certificate for the domain on services like Let’s Encrypt.
When trying to execute SSH on OpenWRT with a private key, e.g.
ssh -i id_rsa user@host
you encounter this error:
ssh: Exited: String too long
You have an nginx host that is configured as reverse-proxy-only like this:
server {
server_name my.domain;
[...]
location / {
proxy_pass http://localhost:1234;
}
}
For this host, you want to use Let’s Encrypt to automatically issue a certificate using the webroot method like this:
certbot certonly -a webroot --webroot-path ??? -d my.domain
The reverse-proxied webserver does not provide a webroot to use for the automated autentication process and you want to keep the flexibility of updating the cert at any time without manually modifying the nginx configuration.
After upgrading my server from Debian Wheezy to Jessie, I encountered the following error during apt-get update:
/usr/lib/apt/methods/https: symbol lookup error: /usr/lib/x86_64-linux-gnu/libhogweed.so.2: undefined symbol: __gmpn_cnd_add_n
You want to query the current resolution of a screen connected as framebuffer device (e.g. /dev/fb0). Mehr lesen
You hard drive or SMART tool reports errors when reading specific blocks similar to this message:
[3142.686141] end_request: I/O error, dev sda, sector 31415926
No matter how often you read the block, the hard drive still returns an error and does not reallocate the block.
Symptomatics:
I have both the Toshiba Z830 and R850 for a couple of years now. On both, I’m using the current LTS versions of KUbuntu (at the time of writing this, 14.04). Although, I’m absolutely satisfied with them, there’s a little issue regarding the backlight:
On startup, the backlight works perfectly well. I can change the settings using FN+F6/F7 without any issues. However, after putting the device into standby and waking it up again, pressing said hotkeys shows the backlight percentage dialog, but does not change the brightness.
Because Ubuntu’s SSD reboots are pretty fast Iimply didn’t care about the issue for the past few years. However, out of curiosity, I successfully fixed the issue today.