This helper container is designed to update the password of the original administrator account of a Portainer instance.
Note for Portainer < 2.0: it will only reset the password associated to the original administrator account (UserID == 1). If you removed this account, this helper won't be of any help.
# stop the existing Portainer container
docker container stop portainer
# run the helper using the same bind-mount/volume for the data volume
docker run --rm -v portainer_data:/data portainer/helper-reset-password
2020/06/04 00:13:58 Password succesfully updated for user: admin
2020/06/04 00:13:58 Use the following password to login: &_4#\3^5V8vLTd)E"NWiJBs26G*9HPl1
# restart portainer and use the password above to login
docker container start portainer
# scale down to zero the existing Portainer service
docker service scale portainer_portainer=0
# run the helper using the same bind-mount/volume for the data volume
docker run --rm -v portainer_portainer_data:/data portainer/helper-reset-password
2020/06/04 00:13:58 Password succesfully updated for user: admin
2020/06/04 00:13:58 Use the following password to login: &_4#\3^5V8vLTd)E"NWiJBs26G*9HPl1
# scale back to one the existing Portainer service and use the password above to login
docker service scale portainer_portainer=1