tree: ae0002727335b72460eba745cacc263bc88abf07 [path history] [tgz]
  1. Makefile
  3. app/
  4. auth.go
  5. cmd/
  6. conn_server.go
  7. constants.go
  8. ghost.go
  9. overlord.go
  10. rpc.go
  11. sysutils_darwin.go
  12. sysutils_linux.go
  13. sysutils_posix.go
  14. sysutils_test.go
  15. test/
  16. utils.go
  17. utils_test.go

Overlord Deployment Guide


The goal of this document is to provide deployment guidance to the Overlord factory monitor system.

Basic Deployment

Get the source

The Overlord source code resides in the chromiumos factory repository. You can clone the factory git repo without the entire chromiumos source tree:

$ git clone


Make sure you have the Go lang toolchain installed (apt-get install google-golang). Building Overlord is as easy as typing make under the go/src/overlord

$ cd factory/go/src/overlord

$ make


Assuming your server is located at SHOPFLOOR_IP, just scp the go/bin dir onto the server

$ scp -r factory/go/bin SHOPFLOOR_IP:~/overlord

In this particular case, we copy the bin folder onto the HOME/overlord on the shopfloor server.

Start the Server

To start the server, simply run the overlordd binary

shopfloor:~ $ cd overlord

shopfloor:~/overlord $ nohup ./overlordd &

One the server started, browse http://SHOPFLOOR_IP:9000 to access the overlord web frontend.

There are some options available for the overlordd command, use overlord -help to see them.

By default, overlordd is started with HTTP basic auth enabled. The default account / password is overlord/cros, please follow the later section in this document to change the password for production environment. To disable HTTP basic auth, simply add the -noauth option when launching overlordd. This is strongly discouraged in production environment, as it expose your server for anyone to access it.

Ghost Clients

The clients are called ghost in the Overlord framework. There are currently two implementations, one implemented in python and the other implemented in go. The python version can be found under the factory source repository: py/tools/; while the go version is under go/src/overlord/ghost.go which is built along side with the overlordd binary under go/bin.

Server Configuration

Changing LAN Discovery Broadcast Interface

Overlord server broadcasts LAN discovery messages into the subnet so clients can identify the server IP. In a typical factory network, a server might have at least two interface, one for LAN and another for external network. By default, overlord broadcast the LAN discovery message to the default gateway's subnet. To specify a different one, use the -lan-disc-iface option:

shopfloor:~/overlord $ nohup ./overlordd -lan-disc-iface=eth1 &

Changing Default Password

The password to the Overlord server is stored in a apache style htpasswd file. This means it supports multiple login credentials. To change it, first remove the default password:

shopfloor:~/overlord $ rm app/overlord.htpasswd

The use the htpasswd utility to create a new htpasswd file. The htpasswd utility can be installed by apt-get install apache2-utils:

shopfloor:~/overlord $ htpasswd -B -c app/overlord.htpasswd username11

New password:
Re-type new password:
Updating password for user username1

The -c option create the new file. To add more credentials to the file simply remove the -c option:

shopfloor:~/overlord $ htpasswd -B app/overlord.htpasswd username2

Enable SSL Support

To ensure the privacy of the communication with the overlord server via the web frontend. It`s encouraged to enable SSL on a production environment.

You can either use a CA-signed SSL certificate or a self-signed SSL certificate. We usually use a self-signed certificate in the factory since we can`t be 100% sure we are the only one that have access to the server. If the partner have access to the server, they can steal your SSL certificate file!

To generate a self-signed SSL certificate, you need the openssl software suite from you distribution:

shopfloor:~/overlord $ openssl req -x509 -nodes -newkey rsa:2048 -keyout
key.pem -out cert.pem -days 365

Note that you need to input the correct common name when generating the certificate, common name is typically the FQDN or IP of the server.

This will generate two files: cert.pem and key.pem. Assign it to the -tls option when starting overlordd, and you are all set.

shopfloor:~/overlord $ nohup ./overlordd -tls=cert.pem,key.pem &

Now you can browse https://shopfloor_ip:9000 to access the web frontend. Note that you need to use https instead of http.

Connecting to a TLS enabled Server

ghost automatically detects if Overlord server has TLS enabled and verify it using system installed ca-certificates bundle.

To connect to a TLS enabled Overlord server, a ghost client must specify the TLS certificate to be used for verification:

$ ghost --tls-cert-file cert.pem SERVER_IP

Optionally, one could enable TLS but skip certificate verification:

$ ghost --tls-no-verify SERVER_IP


The SSL certification generated above is a self-signed SSL certificate. The first time you visit the web frontend, you will see a warning.

This is the result of self-signed SSL certificate, no need to panic. Click on the left top corner of the browser to see the certificate information.

Make sure the fingerprint is correct then hit the Advanced button then Proceed.

Auto Upgrade Setup

Overlord supports an AU(Auto Upgrade) protocol for updating ghost clients. Ghost clients automatically check for update on registration. Admins can also force an upgrade if there are updates available.

Prepare Upgrade Files

Fetch the latest or ghost binary from factory repo. For the ghost binary, rename it into ghost.ARCH, where ARCH is go runtime.GOARCH variable on that platform. For a x86_64 platform, the runtime.GOARCH equals amd64. In such case, rename the binary to ghost.amd64.

Copy the Upgrade File Onto the Server

Create the required directory structure

On the Shopfloor server:

shopfloor:~/overlord $ mkdir app/upgrade

Copy the Upgrade file

$ scp SHOPFLOOR_IP:~/overlord/app/upgrade

$ scp ghost.amd64 SHOPFLOOR_IP:~/overlord/app/upgrade

Generate Checksum

shopfloor:~/overlord $ cd app/upgrade

shopfloor:~/overlord/app/upgrade $ for i in `ls ghost.* | grep -v sha1`; do \
        sha1sum $i | awk '{ print $1 }' > $i.sha1 done

Force Upgrade

After the above step, the upgrade files are ready. Now if a new client connects or client reconnects to the overlord server, it automatically checks for upgrade and apply it. To force an upgrade for already connected clients, simply send a GET request to the server:

$ curl -k -u username1:password1 'https://localhost:9000/api/agents/upgrade'

(Note: use http if you don't have SSL enabled)