After you determine when to troubleshoot an issue instead of migrating or redeploying, you can identify and resolve specific SSH errors based on which phase of a successful SSH connection you need to debug.
Once your SSH connection is established and you are authenticated, the remote shell environment is then executed. There are a couple of issues that can occur at this point as described below, followed by actions you can take to address them.
To troubleshoot SSH issues, you will need to make sure your Droplet is responding normally from the Droplet console with a working network configuration. Before troubleshooting SSH, you should always check your cloud panel for ongoing issues in the region impacting your Droplet, the hypervisor status, and the state of the Droplet through the Droplet console.
Below are some common SSH environment errors you might encounter.
In some cases, you may cause damage to directory ownership or permissions that can cause problems when trying to access the home directory. This can result in errors like the following:
Could not chdir to home directory /home/user: Permission denied
Could not chdir to home directory /home/user: Input/output error
Could not chdir to home directory /home/user: No such file or directory
Some issues might stem from the user home directory not existing, its ownership being incorrect, or its permissions being too restrictive. This also might happen when filesystem issues have corrupted the home directory.
To troubleshoot this issue, try checking the home directory’s existence, permissions, and ownership.
In some cases, users may be configured to not have a login shell. This can manifest in several ways in the shell not responding. You might see an error like this:
This account is currently not available.
Here are some potential causes of this issue:
falseor another non-shell binary. In this case, you can update the user shell.
The SSH service, like any service, requires system resources to operate. This means that when your Droplet is under resource-constrained conditions, the service may fail to open a working shell environment. These conditions include exhausting the system memory, reaching the system’s open file limit, or crashing the runtime environment.
You might see an error message like this:
ssh: connect to host example.com port 22: Resource temporarily unavailable
Resource issues can be difficult to debug, and depends on the kind of access you have to your Droplet. Read below on how to handle resource issues.
Below are some troubleshooting methods and solutions to common SSH environment errors.
In some cases, you may need to use the Droplet console to log in as root to evaluate the home directory with sufficient permissions to address any issues. Make sure
/home and the path for the user’s home directory exist using
stat or a similar utility.
If the directories exist, make sure the user’s home directory has appropriate permissions (at least
700) and ownership (the user, not root).
From the Droplet console, log in as root or a user with
sudo access. You can review the
/etc/passwd file directly or use the
getent command to list the details:
getent passwd user
You’ll see output like this. Note the
To update this, you can use the system command
usermod and specify the correct shell to use, like
usermod -s /bin/bash user
If you run the
getent command again, you’ll see the change reflected in the output:
You can then try logging in again.
Dealing with resource issues is a very context specific situation.
If the source of resource contention is due to network requests (e.g. an attack against a web application), you may be able to disable the service or block traffic at the firewall from the Droplet console. This may allow enough room for you to assess the impact of the situation and implement mitigation strategies or consider scaling your deployment.
If you cannot log in from the Droplet console, the last resort option is to power cycle or reboot the Droplet. Depending on the cause of the resource exhaustion, this may simply hit the same environment or initially support a connection that gives an
Unable to fork process error when you attempt to run a command. Catching the Droplet console or SSH connection to the Droplet after a reboot but before it becomes unresponsive is key to troubleshooting the root cause.
You can learn more about scaling, load balancing, and expanding your Droplet’s resources in the following tutorials:
If you need further help establishing a working SSH connection to your Droplet, you can open a support ticket. Make sure to include:
Including all the above diagnostic information and clarifying where you are encountering the issue when trying to connect can help us quickly get up to speed with where your need on the issue is.