To correctly stop an autossh running process use the following (taken from https://superuser.com/a/1008029):
sudo pkill -3 autosshStopping autossh process
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Problems using snap autossh
Problem
You would like to use autossh to keep a connection open (ie database) between two hosts, but while the ssh equivalent command to start a tunnel works, the autossh does not.
You might be seeing the following errors (using AUTOSSH_DEBUG=1):
autossh[7471]: ssh exited prematurely with status 255; autossh exiting
or if you look at /var/logs/syslog you could also see entries like the following:
apparmor="DENIED" operation="open" profile="snap.autossh.autossh" name="/home/autossh/.ssh/id_rsa.pub" pid=7447 comm="ssh" requested_mask="r" denied_mask="r" fsuid=1002 ouid=1002Solution
You have used snap to install autossh which is not allowed by apparmor.
Remove the snap package and install autossh as a normal debian package:
sudo snap remove autossh
sudo apt install autossh
Connect your Shivr bluetooth headphones in Linux
To connect your new Shivr headphones but it would probably work with other bluetooth headphones too, find the MAC address from your headphones (by connection with an Android device first) and do the following from the command line:
sudo apt install bluez-tools
bt-device -l (that will list the available devices)
bt-device -c AA:11:22:33:44:BBand make sure you change your Music Player Daemon Output (Audio Volume Settings -> Applications) settings to use your new headphones.
Setup your own gitlab runner
To add your own gitlab runner, follow the steps below
- Create your runner, in EC2, Google, or any other cloud provider and have ssh access to it.
- Login to your runner from the previous step and install the gitlab-runner (there are various methods described here: https://docs.gitlab.com/runner/install/. We install using Gitlab’s repositories)
- Register the gitlab-runner by following the instructions here: https://docs.gitlab.com/runner/register/index.html . You would need to get the token for each project you want to register your runner with (Gitlab -> Settings -> CI/CD -> Runners -> Expand). You can use different executors for your running during the registration such as docker, shell etc.
- Go to your Gitlab project and find the runner you register above and enable it for the project. You should also add the tags: name_of_your_runner in your .gitlab-ci.yml file.
Cannot login to MariaDB server with root account
Problem
You are trying to login to MariaDB with the root user, but even after resetting the password, it is still not possible to login.
Solution
It seems that certain MariaDB packages that come with Linux distributions use the unix_socket as the authentication method.
MariaDB [mysql]> SELECT user, host, plugin FROM user WHERE user='root';
+------+-----------+-------------+
| user | host | plugin |
+------+-----------+-------------+
| root | localhost | unix_socket |
+------+-----------+-------------+
1 row in set (0.00 sec)
Change the plugin as described here (https://stackoverflow.com/a/43424234) with the following:
MariaDB [mysql]> UPDATE mysql.user SET plugin = '' WHERE user = 'root';
Query OK, 1 row affected (0.00 sec)
Rows matched: 1 Changed: 1 Warnings: 0
Get a list of directories with user permissions
Problem
You want to run a command in a hosted server but you don’t have su permissions. There are directories that have different owners/permissions, so you would like to see them.
Solution
Use the tree command and save the output in a file if you have many directories:
tree -pufid /home/directory_to_check > /home/user/permissions.txt
taken from the answer here: https://unix.stackexchange.com/a/82374
Change AWS EC2 instance type
Problem
You want to change the instance type of your EC2 AWS instance.
Solution
- Stop your instance (right click Instance State -> Stop)
- Wait for a few minutes
- Change instance type (right click Instance Settings -> Change Instance Type)
- Start your instance (right click Instance State -> Start)
Get the host IP address from inside a docker container
Problem
You wold like to know the IP Address of your host from inside a running docker container.
Solution
Run the following inside the container:
route | awk '/^default/ { print $2 }'
Error setting up kubeconfig: writing kubeconfig: Error writing file : open : no such file or directory
Problem
You get the following error when trying to start minikube:
Error setting up kubeconfig: writing kubeconfig: Error writing file : open : no such file or directory
Solution
Unset the KUBECONFIG variable like:
unset KUBECONFIG
kubectl error: “The connection to the server localhost:8080 was refused – did you specify the right host or port?”
Problem
You want to use the kubectl to get your cluster information but you are getting the following error message
$ kubectl cluster-info
To further debug and diagnose cluster problems, use 'kubectl cluster-info dump'.
The connection to the server localhost:8080 was refused - did you specify the right host or port?
Solution
That could happen if you have already setup kubectl before or have used a different environment.
So you will need to first unset the environment variable KUBECONFIG with:
$ unset KUBECONFIG
and then use the gcloud client to set your environment again:
$ gcloud container clusters get-credentials your_cluster_name --zone europe-west2-a --project your_project_name
So after this you should be able to use kubectl to get the cluster information
kubeconfig entry generated for your_cluster_name.
$ kubectl cluster-info
Kubernetes master is running at https://xxx.xxx.xxx.xxx
GLBCDefaultBackend is running at https://xxx.xxx.xxx.xxx/api/v1/namespaces/kube-system/services/default-http-backend:http/proxy
Heapster is running at https://xxx.xxx.xxx.xxx/api/v1/namespaces/kube-system/services/heapster/proxy
KubeDNS is running at https://xxx.xxx.xxx.xxx/api/v1/namespaces/kube-system/services/kube-dns:dns/proxy
Metrics-server is running at https://xxx.xxx.xxx.xxx/api/v1/namespaces/kube-system/services/https:metrics-server:/proxy