An ArcGIS Server site comprises one or more ArcGIS Server machines that have the ArcGIS Server component installed. Service requests for maps, address coordinates, geoprocessing jobs, and so on, are each assigned to an available machine within the site. That machine then does the work of drawing the map, finding the address coordinate, or running the geoprocessing tool, and returns the result to the client.
Adding a new machine to an existing ArcGIS Server site can be done temporarily to migrate to new machines or more permanently to increase the resources and processing power of your server site. Sites with two or more machines can also be configured for high availability, to protect against downtime and data loss in the event of computer failure.
When you have installed and configured ArcGIS Server on a new machine, you can use the Join Site operation to add it to an existing site upon logging into ArcGIS Server Manager. You can also add ArcGIS Server machines to your site using ArcGIS Server Manager, ArcMap, or the join-site command line utility.
Criteria to add an ArcGIS Server machine to a site
If you are using Join Site to migrate a machine, the new and existing machines do not need to match, but if you intend to keep all machines in the site permanently, ensure they meet the following criteria:
- The new machine must be running on the same operating system platform as the other ArcGIS Server machines in the site. We recommend you use the same operating system version and hardware resources for all machines in your site. For example, if you have a site comprised of ArcGIS Server machines, each running on Red Hat Enterprise Linux Server 8 with a 3 GHz processor and 8 GB of RAM, the machine you add to the site should also have the same operating system and hardware specifications.
- It must be at the same version number as the other ArcGIS Server machines in the site.
- It must have the same license applied to it as the other ArcGIS Server machines in the site.
- It must be able to read and write to the site's configuration store and server directories.
- It must be able to communicate with all the other ArcGIS Server machines in the site through the ports listed in Ports used by ArcGIS Server. This may require adjustment of firewall settings.
- It must be able to read any data referenced by services on the site. A good way to verify this is to check whether the machine has permissions to all the data storage locations registered with the site. See Data sources for ArcGIS Server to learn more about these registered locations.
- All running ArcGIS Server machines need to be able to read and write to the same shared directories through NFS using the same mount point on all systems. For example, if you are mounting a file server shared directory to /arcgis on one machine and using it for your configuration store and server directories, all machines must also mount that same directory to /arcgis.
- All ArcGIS Server machines need to be running under users who have the same user id (uid) or group id (gid) in order to be able to read and write to the shared configuration store and server directory locations.
Configuring the server directories and configuration store to use shared paths
An ArcGIS Server site with multiple machines must share the folders containing the site's server directories and configuration store. Ensure that the ArcGIS Server account has permissions to read and write to the shared folder.
Although it is possible to share your existing locations for the configuration store and server directories, it is strongly recommended that you move these locations to a fault-tolerant file server. This is especially important in cloud deployments, where automatic scaling mechanisms might add and remove machines from your site without awareness of which holds the configuration store.
ArcGIS Server does not support shared network directories that are hidden or use special characters (such as $).
Once you share the server directories and configuration store, you need to configure the site to use the new, shared paths. You can do this in ArcGIS Server Manager or ArcGIS Desktop by following the instructions below. Note that your server will experience a period of downtime while these steps are executing.
Editing the server directory and configuration store paths in ArcGIS Server Manager
- Open ArcGIS Server Manager for the ArcGIS Server site and log in. If you need help with this step, see Log in to Manager.
- To edit the configuration store path, click Site > Server Configuration > Configuration Store. Enter the shared path of the configuration store location. The contents of the configuration store are moved to the new location and all services are restarted.
- To edit the server directory paths, click Site > Server Configuration > Directories. For each directory, click its Edit button and enter the new shared path for the directory. When you edit a directory path, the contents of the directory are copied to the new location unless you are editing a cache directory. When you change a cache directory location, you must copy the cache to the new location yourself.
Editing the server directory and configuration store paths in ArcGIS Desktop
- In ArcCatalog or the Catalog window, expand the GIS Servers node.
- Right-click your administrative connection to ArcGIS Server and choose Server Properties. If you need help with this step, see Connect to ArcGIS Server from ArcGIS Desktop.
- To edit the configuration store path, click the Configuration Store tab in the ArcGIS Server Properties window. Enter the shared path of the configuration store location. The contents of the configuration store are moved to the new location and all services are restarted.
- To edit the server directory paths, click the Directories tab in the ArcGIS Server Properties window. Update each directory with its new shared path. When you edit a directory path, the contents of the directory are copied to the new location unless you are editing a cache directory. When you change a cache directory location, you must copy the cache to the new location yourself.