Opkg_validate_cached_file Error When Trying to Install Software With Opkg Commands in NI Linux Real-Time Target

Issue Details

I want to install software in my NI Linux Real-Time (RT) target through opkg commands using the RT target terminal, however, when trying to run an opkg command like opkg update or opkg install <package> I got the following error:

• opkg_validate_cached_file: Failed to download <package_url>

I can install NI software through NI MAX.

• Why cannot I install software through opkg in RT target terminal?

Solution

This issue is expected when RT target does not have a DNS server and default gateway configured in its network settings, making the RT target unable to reach out download.ni.com server to get the software stack available for your device. This is common when:

• Having directly connected the RT target to your PC. 
• Having the network ports with the Configure IPv4 Address option as:
  • DHCP or Link Local
  • Link Local
  • Static

To allow the connection to download.ni.com from your RT target through your PC you can try the following methods:

Method 1: NI MAX Real Time Software Window. The NI MAX Real-Time Software window creates a bridge between your cRIO and the internet connection through your PC allowing the cRIO reach out the ni.download.com software server.

1. Launch NI MAX
2. Search for your cRIO controller
3. Go Software option Add/Remove Software
4. Go ahead until you get the Real-Time Software window and leave it open.
5. With the Real-Time Software window opened connect to your RT target terminal
6. Proceed with the installation of your software stack with opkg commands like opkg update or opkg install <package>

Method 2: View Network Connections in Windows Control Panel. You can enable one of your host PC network ports with internet access to allow other network ports to get internet access through this enabled port.

1. In your PC go to View Network Connections from the Windows Search bar.
   
2. Select the ethernet port with internet access
   1. Right click >> Properties >> Sharing
   2. Check the Allow other network users to connect through this computer's internet connection option
   3. From the drop-down menu select the network port which is connected to your RT target

Additional Information

In case you are having issues opening the Real-Time Software window you can refer the following link:

• One or More Feeds Are Inaccessible Error When Installing Software to NI Linux Target