So, given that kubectl cp was never reliable ever for me, leading to many notes here, incl. 250115-1052 Rancher much better way to copy data to PVCs with various hacks and issues like 250117-1127 Splitting files, 250117-1104 Unzip in alpine is broken issues etc. etc. etc.

For many/large files, I’d have used rsync, for which ssh access is theoretically needed. Not quite!

rsync files to a kubernetes pod - Server Fault

ksync.sh (EDIT Updated by ChatGPT to support files with spaces):

if [ -z "$KRSYNC_STARTED" ]; then
    export KRSYNC_STARTED=true
    exec rsync --blocking-io --rsh "$0" "$@"
fi

# Running as --rsh
namespace=''
pod=$1
shift

# If user uses pod@namespace, rsync passes args as: {us} -l pod namespace ...
if [ "X$pod" = "X-l" ]; then
    pod=$1
    shift
    namespace="-n $1"
    shift
fi

# Execute kubectl with proper quoting
exec kubectl $namespace exec -i "$pod" -- "$@"

Usage is same as rsync basically :

./ksync.sh -av --info=progress2 --stats /local/dir/to/copy/  PODNAME@NAMESPACE:/target/dir/

(Or just --progress for per-file instead of total progress).

Rsync needs to be installed on server for this to work.

For flaky connections (TODO document better): -hvvrPt --timeout1 and while ! rsync ..; do sleep 5; doen ¹