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Docker: building multi-platform images that use fat manifest list/index

Docker can build multi-platform images that use a manifest index (fat manifest list) by using the Docker buildx command with backing containerd runtime and QEMU for cross-platform emulation. Using a manifest index for multi-platform images simplifies application level orchestration by using the same name and version for all architectures.  For example: # same image name Docker: building multi-platform images that use fat manifest list/index

Ubuntu: fixing apt NO_PUBKEY errors by converting deprecated keyring to signed-by attribute

If apt update throws warnings about invalid signature verification and NO_PUBKEY, you may need to migrate from using the deprecated system keyring to using a ‘signed-by’ attribute in your apt repo definition file. Here are examples of errors you might see when doing an ‘apt update’. W: An error occurred during the signature verification. The Ubuntu: fixing apt NO_PUBKEY errors by converting deprecated keyring to signed-by attribute

Bash: Fixing an ASCII text file changed with Unicode character sequences

File encoding issues are difficult to diagnose and troubleshoot.  Most files in the operations world are expected to be text-only ASCII 7 bit, so if a file goes into UTF-8 encoding and has embedded Unicode character inserted, it can often throw off the tool chain or systems using the file. Here are two example files, Bash: Fixing an ASCII text file changed with Unicode character sequences