PDFtk is a simple tool for doing everyday things with PDF documents.
mkdir /opt/pdftk/input
mkdir /opt/pdftk/output
docker run -d -v /opt/pdftk/input:/input -v /opt/pdftk/output:/output sfoxdev/pdftk /input/test.pdf cat 2 output /output/result.pdf
-/input/test.pdf
is the original PDF file
-cat 2
is the page number want to extract
-output /output/result.pdf
is the extracted output file