Introduction
This is an article where the main focus is how to solve an error message appear. The error appear is exist as in the title of this article. It is the short form of the error message. The error message appear upon executing a certain command in a Linux operating system. It is a command for pulling image using ‘podman’ tool or ‘podman’ command. So, the following is the full form of the error message appear upon executing the command execution as part of the output :
[admin@10 ~]$ podman pull localhost
? Please select an image:
▸ registry.access.redhat.com/localhost:latest
registry.fedoraproject.org/localhost:latest
registry.centos.org/localhost:latest
docker.io/library/localhost:latest
Actually, the above command execution is triggering a specific output of listing the image repository server. The list actually available in the container configuration file. The container configuration file itself exist in ‘/etc/containers/registries.conf’. The configuration line which is becoming the base for the image repository server exist as part of the original configuration as follows :
unqualified-search-registries = ["registry.fedoraproject.org", "registry.access.redhat.com", "registry.centos.org", "docker.io"]
The above configuration line is a v2 configuration syntax pattern. As it appears in the above configuration line, it is a definition or a declaration of image repository server list separated by a comma. There are four of them as it also appear in the list of the image repository server as part of the output command above. So, after selecting one the image repository server, the following output after the command execution appear :
[admin@10 ~]$ podman pull localhost ✔ registry.fedoraproject.org/localhost:latest Trying to pull registry.fedoraproject.org/localhost:latest... manifest unknown: manifest unknown Error: Error initializing source docker://registry.fedoraproject.org/localhost:latest: Error reading manifest latest in registry.fedoraproject.org/localhost: manifest unknown: manifest unknown [admin@10 ~]$
Basically, the main error message in the following part :
manifest unknown: manifest unknown
Solution
The solution for solving the above problem is quite simple. Before pulling the image, just check it first. Search it in the image repository server to make sure that the image is actually exist. Run the following command :
[admin@10 ~]$ podman search registry.access.redhat.com/localhost [admin@10 ~]$
So, basically pulling the image with the name of ‘localhost’ is the same as pulling a non-exist image. That is why the error message above is showing ‘manifest unknown: manifest unknown’. Because the image does not exist in the first place and podman generate an error message informing that. Just compare with another image with the name of ‘mysql’ as follows :
[admin@10 ~]$ podman search registry.access.redhat.com/mysql INDEX NAME DESCRIPTION STARS OFFICIAL AUTOMATED redhat.com registry.access.redhat.com/rhscl/mysql-57-rhel7 Docker image for running MySQL 5.7 server. T... 0 redhat.com registry.access.redhat.com/rhscl/mysql-56-rhel7 MySQL 5.6 SQL database server 0 redhat.com registry.access.redhat.com/openshift3/mysql-55-rhel7 MySQL 5.5 SQL database server 0 redhat.com registry.access.redhat.com/openshift3/mysql-apb Ansible Playbook Bundle application definiti... 0 redhat.com registry.access.redhat.com/rhmap44/mysql Provides an extension to the RHSCL MySQL Doc... 0 redhat.com registry.access.redhat.com/rhmap42/mysql Provides an extension to the RHSCL MySQL Doc... 0 redhat.com registry.access.redhat.com/rhmap43/mysql Provides an extension to the RHSCL MySQL Doc... 0 redhat.com registry.access.redhat.com/rhmap46/mysql Provides an extension to the RHSCL MySQL ima... 0 redhat.com registry.access.redhat.com/rhmap45/mysql Provides an extension to the RHSCL MySQL ima... 0 redhat.com registry.access.redhat.com/rhmap47/mysql Provides an extension to the RHSCL MySQL ima... 0 redhat.com registry.access.redhat.com/rhscl/mysql-80-rhel7 This container image provides a containerize... 0 [admin@10 ~]$