Browse All Articles > Rebuild an OVA appliance: A free approach to enable legacy hypervisors utilize newer OVA format
You have probably faced the following error and re-downloaded an OVA virtual appliance multiple times with a hope to successfully deploy that in the next attempt? Stop!, the files are binary identical! hence the error persists:
The following manifest file entry (line 1) is invalid: SHA-256...
Recycling an OVA - Flow by Al Fa under a CC BY-SA 4.0 license
Introduction
Recently built OVA packages prefer SHA-256 algorithm instead of SHA1. If you consult VMWare, they will point you to some procedure to download and use a tool to named ovftool, to recode with another algorithm and generate a converted version of the original appliance. In this article, we will go through an alternative approach using your favorite archive manager and text editor.
Assumption
The following has been assumed for simplicity:
You are on a 64-bit Windows (But actually not limited to)
You are using 7Zipas your favorite archive manager.
Open the file with .mf extension with notepad++, for each file mentioned there do the following steps:
Right-click on that file and calculate the SHA-1 using the 7-Zip context menu
Press CTRL-C (yes, do that!) on the pop-up window that displays the SHA-1 checksum
Paste your clipboard into a new notepad instance. Among those lines, copy the SHA1 checksum into your clipboard
Paste the checksum overwriting the existing one in .mf file you kept open from previous steps.
Change the SHA-256 identifier to SHA1 onthatline. Repeat the above steps until all lines are updated accordingly.
Save the .mf file
Open the appliance.ova.taronce again with 7-Zip
Drag the modified .mf files into the tar archive to freshen and overwrite the previous one
Close 7-zip and rename file back to the original appliance.ova name.
Deploy your appliance now.
Final Word
You don't need to add a new tool to your toolbox to resolve import-ability issues of some OVA appliance files. In fact acquiring, installing, learning and invoking the tool to convert your OVA appliance to a new format may sound overkill just to make an import possible. Here we leveraged the fact that an OVA is just a packaged collection of OVF, Virtual disks and some metadata to disassemble, adjust and reassemble an OVA with the fun and joy of doing that in a transparent process and using our everyday tool-set.
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