Installation Prerequisites

Install third-party software

Before installing Appian, you must download and install the following third-party software:

In addition, you must download the following Appian software from the Downloads tab on MyAppian:

  • Appian 20.4 installer for your operating system
  • Latest hotfix package for Appian 20.4 (if available)


The Appian installation includes OpenJDK 8. To use Oracle JDK 8 instead, download and install Oracle JDK 8. Take note of the installation path to configure the JAVA_HOME variable. Use this path everywhere you would set JAVA_HOME during installation.

See System Requirements for more information about Oracle JDK support.

Obtain a temporary product license

Product license files are required to start Appian after it has been installed. Long term product licenses can only be requested after Appian is installed. To request and install temporary or long-term licenses, please follow the steps outlined in the Requesting and Installing a License page.

Note: If you are migrating from an older version and have a product license from a previous version of Appian, it is valid to use with this version.

Set the JAVA_HOME and PATH environment variables

If using Oracle JDK 8, set JAVA_HOME to the installation path as previously noted.


To set the JAVA_HOME and PATH environment variables in Linux:

  1. Using Bash, open the profile file located in the /etc directory. Note: You must have superuser rights to modify the profile file.
  2. Add the following lines to the end of the file where the value is the Java installation path:

    export JAVA_HOME=<APPIAN_HOME>/java
    export PATH=$JAVA_HOME/bin:$PATH:
  3. Save the file.


To set the JAVA_HOME and PATH environment variables in Windows:

  1. Click Start, and then click Control Panel. Note: Instructions for accessing the Control Panel may vary slightly based on the version of Windows you are using.
  2. Click System and Security.
  3. Click System.
  4. In the left-hand pane, click Advanced system settings.
  5. Click the Advanced tab.
  6. Click Environment Variables.
  7. Under System variables, look for JAVA_HOME:
    • If it is present, verify that the installation path is correct for JDK 8.
    • If it is not present, click New, and then enter the following information:

      Setting Value
      Variable name JAVA_HOME
      Variable value <APPIAN_HOME>\java
  8. With Environment Variables dialog still open, select the Path variable, and then click Edit.
  9. Add the following value if it is not present (note that each value is separated by a semicolon):


Important: If the JAVA_HOME environment variable is set to the installation path of another JDK version or a runtime environment that is not the JDK installation path, Appian will not start correctly.

Configure the application user account for Linux

Configure the UNIX user account and group that owns the application before running the setup program. A non-root user must have the following rights assigned when running the setup, and the APPIAN_HOME and JAVA_HOME directories must exist prior to running the installer.

Directory or File Read Write Execute
Installation Package Yes No Yes

Increase maximum open file limit for the application user account

The maximum allowable number of file descriptors available to the user running Appian may need to be increased. In order to determine if the limit needs to be increased, log in using the Appian application user account, and then run the following command:

ulimit -n

If the value returned by ulimit -n is less than 100000, then increase the limit by running the following command:

ulimit -n 100000

Repeat this procedure for all servers running any component of the Appian architecture in all environments. For example, if you are using development, staging, and production environments, then you would repeat this procedure on each one.

Note: If the value of 100000 exceeds the total number of open files allowable for the system, consult your operating system documentation for instructions on configuring the limit on the total number of open files (this typically located in /proc/sys/fs/file-max).

Verify the server system locale setting

The system locale must be defined in order to install Appian. You will not be able to install Appian if the system locale is not defined.

In most cases, the system locale setting will already be set correctly. However, there is a rare issue that may be encountered on new or virtualized operating system installations. The instructions below describe how to verify the system locale on both supported platforms.

To verify the locale setting in Linux

  • Open Bash, and use the locale command to display the locale settings. If the locale is set, you will see something similar to the list below:


If the locale settings are not displayed, you must update or create the i18n file by doing the following steps:

  1. Open /etc/sysconfig/i18n in a text editor.
  2. Add the appropriate LANG= and LC_ALL= parameters. For example, if you are using English in the United States, you would define both parameters using en_US:

    LANG=en_US  LC_ALL=en_US
  3. Reboot the machine.

To verify the system locale setting in Windows

  1. Click the Start button, click Control Panel, click Clock, Language, and Region, and then click Region and Language Options.
  2. In the Region and Language dialog, click the Administrative tab.
  3. Verify that the desired system locale is set under Language for non-Unicode programs.

If the locale is not set correctly, make the necessary changes and reboot the machine.

Open the required ports

Appian components communicate with each other over specified network ports. If you are preparing a distributed installation, you must first ensure that the required ports are open between the servers that host the different Appian components.

Configure Linux for search server

Appian uses standalone deployment of Elasticsearch for the search server. This provides increased security and reliability for the search server. The following system configurations are required for standalone deployment of search server.

Virtual memory

Elasticsearch uses a mmapfs directory by default to store its indices. The default operating system limits on mmap counts could be low and result in out of memory exceptions. On Linux, increase the limits by running the following command as root:

sysctl -w vm.max_map_count=262144

Minimum value of 262144 is required. To set this value permanently, update the vm.max_map_count setting in /etc/sysctl.conf. To verify after rebooting, run sysctl vm.max_map_count.

No such setting is required for the Windows operating system.

Number of threads

Elasticsearch uses a number of thread pools for different types of operations. It is important that it is able to create new threads whenever needed. Make sure that the number of threads that the search server can create is at least 4096.

This can be done by setting ulimit -u 4096 as root before starting the search server, or by setting nproc to 4096 in /etc/security/limits.conf.

No such setting is required for the Windows operating system.

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