Set up a Git replica server

On sites distributed across multiple geographic locations, Git replica servers are local and remote mirror servers that can provide up to date copies of the central repositories, which if set up, can address load balancing and fetch performance issues. You can set up one or more Git replica servers (also referred to as slave or mirror servers) with TeamForge 8.1 and later.

Points to note before you begin

Every Git replica server has one and only one 'master' Git server.
It's not possible to set up both Git master and slave on the same server. However, you can have multiple master and slave servers in your TeamForge environment.

You may have your master Git integration server installed on the TeamForge application server's host or on a separate host dedicated to Git/SCM integration.

Git replication servers can be set up with TeamForge 8.1 or later only.
You must upgrade your Git integration server to v8.4.6 or later. Click here to know more.
Have the master Git integration server's externalSystemId handy.
- Open the /opt/collabnet/gerrit/etc/gerrit.config file on the master Git integration server and note down the externalSystemId from the [teamforge] section.
- Alternatively, Log on to the TeamForge application server as an Admin user, click Admin > Integrations > SCM Integrations, select the master Git integration server, click Edit and look for a token such as exsy####, for example exsy1002, in the browser URL. This is the external system ID of your Git integration server.
Open the TeamForge application server's site-options.conf file and keep the values of the following tokens handy.
- ```
SCM_DEFAULT_SHARED_SECRET
```
- Note down the values of the following tokens only if obfuscation is enabled on your TeamForge application server (OBFUSCATION_ENABLED=true):
```
OBFUSCATION_ENABLED
OBFUSCATION_KEY
OBFUSCATION_PREFIX
AUTO_DATA
```

Install Red Hat Enterprise Linux/CentOS 6.5 or later and log on to the server as root.
Important:
- The host must be registered with the Red Hat Network if you are using Red Hat Enterprise Linux.
- See the Red Hat installation guide for help. Important:
- Don't customize your installation. Select only the default packages list.
Check your basic networking setup. See Set up networking for more information.
If the Git replica server has SELinux enabled, run it in 'Permissive' mode temporarily while installing or upgrading TeamForge.
1. Verify if SELinux is running in enforcing mode.
  - getenforce
2. If the output of the getenforce command is "Permissive", continue with the next step.
3. If not, run the following command to bring it to 'Permissive' mode.
  - setenforce 0
Upgrade the operating system packages.
- yum upgrade
Reboot the server.
- reboot
Configure your TeamForge installation repository. See TeamForge installation repository configuration for Red Hat/CentOS.
Install the Git packages.
- yum install teamforge-git
Set up the site-options.conf token for Git.
- vi /opt/collabnet/teamforge/etc/site-options.conf
Note: In this topic:
- my.app.domain.com is an example of the Fully Qualified Domain Name (FQDN) of your TeamForge application server.
- my.git.domain.com is an example of the Fully Qualified Domain Name (FQDN) of your Git integration server.
- my.gitreplica.domain.com is an example of the Fully Qualified Domain Name (FQDN) of your Git replica server.
1. Modify the HOST tokens.
```
HOST_my.gitreplica.domain.com=gerrit
HOST_my.app.domain.com=app database datamart etl indexer subversion cvs binary
```
2. Turn on the SSL for your site by editing the relevant variables in the site-options.conf file. To generate the SSL certificates, see Generate SSL certificates.
```
SSL=on
SSL_CERT_FILE=
SSL_KEY_FILE=
SSL_CA_CERT_FILE=
SSL_CHAIN_FILE=
```
  Note:
  - The SSL_CA_CERT_FILE and SSL_CHAIN_FILE are optional.
  - If you use certificates that are generated in-house, self-signed, or signed by a non-established Certificate Authority, they must be registered with each client system that will connect to the TeamForge server.
  - For the setup discussed in this topic, add the certificate of my.app.domain.com to the JVM of my.git.domain.com and my.gitreplica.domain.com. In addition, add the certificate of my.gitreplica.domain.com to the JVM of my.git.domain.com. Click here for more information.
3. Set the gerrit replication server mode.
```
GERRIT_REPLICATION_MODE=slave
```
4. Set the external system ID of the master Git integration server. See 'Points to note before you begin'.
```
GERRIT_REPLICATION_MASTER_EXTERNAL_SYSTEM_ID=exsy####
```
5. Set the obfuscation related tokens as discussed earlier in Points to note before you begin.
6. Save the site-options.conf file.
Recreate the runtime environment.
- cd /opt/collabnet/teamforge-installer/<TF_VERSION>
- ./install.sh -r -I -V
Run the TeamForge post installation script. For more information, see post-install.py.
- /opt/collabnet/teamforge/runtime/scripts/post-install.py

Now, the gerrit service is running in replica mode. You can now find the newly created Git replica server listed on TeamForge server by accessing the following url. http://<TF_HOST>/sf/sfmain/do/listSystems

Once you have set up one or more Git replica servers, you can replicate repositories. For more information, see Replicate repositories with Git replica servers.