Fixing Docker Permission Denied Error When Connecting to Docker Daemon

Answer:

The error message you're encountering indicates that your user does not have the necessary permissions to access the Docker daemon socket. This is a common issue when trying to run Docker commands without the appropriate permissions. Here are several ways to resolve this issue:

1. Use `sudo`

The simplest way to run Docker commands with the necessary permissions is to prefix them with sudo. For example:

sudo docker run hello-world

2. Add Your User to the `docker` Group

A more convenient and secure way is to add your user to the docker group, which grants the necessary permissions to run Docker commands without sudo.

Step-by-Step Instructions:

Create the docker group (if it doesn't already exist):
```
sudo groupadd docker
```
Add your user to the docker group:
```
sudo usermod -aG docker $USER
```
Apply the new group membership: You need to log out and log back in for the group membership to take effect. Alternatively, you can use the following command to apply the new group membership without logging out:
```
newgrp docker
```
Verify that your user is now part of the docker group:
```
groups $USER
```
You should see docker listed among the groups.
Test running a Docker command without sudo:
```
docker run hello-world
```

3. Check Docker Daemon Status

Ensure that the Docker daemon is running. You can start it using:

sudo systemctl start docker

And enable it to start on boot:

sudo systemctl enable docker

4. Check Socket Permissions

Ensure that the Docker socket has the correct permissions:

ls -l /var/run/docker.sock

The output should look something like this:

srw-rw---- 1 root docker 0 Jan  1 00:00 /var/run/docker.sock

The docker group should have read and write permissions.

5. Restart Docker Service

Sometimes, restarting the Docker service can resolve permission issues:

sudo systemctl restart docker

6. Reboot Your System

If all else fails, a system reboot can sometimes resolve lingering permission issues.