In this article, we will discuss how to resolve a common issue that occurs when trying to attach a container to Portainer, a popular open-source web-based UI for managing Docker containers and services. This issue is particularly relevant to users of Portainer version 3.7 who are trying to mount a tmpfs volume with specific driver options.
Prerequisites
Before diving into the solution, let's make sure we have the following prerequisites in place:
- Portainer installed and running.
- Docker Engine installed and running.
The Issue: Unable to Attach Container with tmpfs Volume
When trying to attach a container to Portainer with a tmpfs volume using the following configuration:
volumes:
- name: tmp_drive
driver_opts:
type: tmpfs
device: tmpfs
You might encounter an error message similar to:
Error response from daemon: No such device: tmpfs
This error occurs because Portainer tries to create a device node for the tmpfs volume, but tmpfs doesn't have a device node.
The Solution: Modify the Configuration
To resolve this issue, we need to modify the configuration to use an empty directory as the volume instead of trying to create a tmpfs volume directly. Here's how:
volumes:
- name: tmp_drive
path: /tmp
This configuration creates a new volume named "tmp_drive" and mounts it to the "/tmp" directory on the host system. By doing this, we can still achieve the same functionality as a tmpfs volume without the need for a device node.
In this article, we discussed a common issue that occurs when trying to attach a container to Portainer with a tmpfs volume using specific driver options. We learned that this issue is caused by the lack of a device node for tmpfs volumes and that we can resolve it by modifying the configuration to use an empty directory instead.