Build vyos-utils deb file

Trying to build vyos-utils for arm64 as following and got errors.
Can you please help me? Thanks

git clone -b equuleus --single-branch https://github.com/vyos/vyos-utils
cd vyos-utils
sudo debuild -b -uc -us

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dpkg-buildpackage -us -uc -ui -b
dpkg-buildpackage: info: source package vyos-utils
dpkg-buildpackage: info: source version 1.3-2
dpkg-buildpackage: info: source distribution unstable
dpkg-buildpackage: info: source changed by Daniil Baturin daniil@vyos.io
dpkg-source --before-build .
dpkg-buildpackage: info: host architecture arm64
debian/rules clean
dh clean --with quilt
dh_quilt_unpatch
No patch removed
dh_clean
debian/rules build
dh build --with quilt
dh_quilt_patch
No series file found
dh_update_autotools_config
debian/rules override_dh_auto_build
make[1]: Entering directory ‘/vyos/vyos-utils’
eval opam env
[WARNING] Running as root is not recommended
Fatal error:
At /root/.opam/config:2:0:
Invalid field opam-root-version
At /root/.opam/config:42:0:
Invalid field default-invariant
At /root/.opam/config:45:0:
Invalid field depext
At /root/.opam/config:46:0:
Invalid field depext-run-installs
At /root/.opam/config:47:0:
Invalid field depext-cannot-install
mkdir -p _build
ocamlfind ocamlopt -o _build/numeric -package num -linkpkg src/numeric.ml
make[1]: ocamlfind: Command not found
make[1]: *** [debian/rules:11: override_dh_auto_build] Error 127
make[1]: Leaving directory ‘/vyos/vyos-utils’
make: *** [debian/rules:6: build] Error 2
dpkg-buildpackage: error: debian/rules build subprocess returned exit status 2
debuild: fatal error at line 1182:
dpkg-buildpackage -us -uc -ui -b failed

Hello @starbucks , did you build this package in the docker container environment?
Build procedure said, that ocamlfind: Command not found

Yes, I did it in the docker