Failed to start replicated.service: Unit not found.

Environment:

Yugabyte Platform with replicated install all versions

Problem:

When trying to launch replicated using the air-gapped installation the service does not start and fails with the error

Created symlink from /etc/systemd/system/docker.service.wants/replicated.service to /etc/systemd/system/replicated.service.

Failed to start replicated.service: Unit not found.

The complete stack trace is as below:

8f165e334137: Loading layer [==================================================>] 15.36 kB/15.36 kB

61159be02373: Loading layer [==================================================>] 1.536 kB/1.536 kB

cb18b7d2b618: Loading layer [==================================================>] 1.501 MB/1.501 MB

Loaded image: registry.replicated.com/library/retraced-postgres:1.3.48

81089a01cc1f: Loading layer [==================================================>] 13.82 kB/13.82 kB

bb9d691c0d07: Loading layer [==================================================>] 51.05 MB/51.05 MB

d0f030658f23: Loading layer [==================================================>] 14.85 kB/14.85 kB

f25afe300213: Loading layer [==================================================>] 3.072 kB/3.072 kB

Loaded image: registry.replicated.com/library/retraced-nsq:1.3.48

Tagging replicated and replicated-ui images

Stopping replicated and replicated-ui service

Installing replicated and replicated-ui service

Starting replicated and replicated-ui service

Created symlink from /etc/systemd/system/docker.service.wants/replicated.service to /etc/systemd/system/replicated.service.

Failed to start replicated.service: Unit not found.

Cause: 

One of the reasons this can happen is if the docker service is not properly installed or running. This can potentially occur if the docker is installed from the source instead of binary and all the required steps of installation are not completed. 

Solution:

Verify if the docker service is up and running using the below command:

sudo systemctl status docker

If the docker service is in stopped status, then start the service and retry running the install script. 

If the docker service is not found, then it's possible the docker setup on the machine is either broken or the service is not installed in the first place. In either of these scenarios, it's recommended to do a fresh installation of the docker service using the package manager. 

eg: https://docs.docker.com/engine/install/centos/#install-from-a-package