sudo yum install -y git podman
git clone https://github.com/danpawlik/openwrt-builder
cd openwrt-builder
podman build -t openwrt-builder -f Dockerfile

Example

how to use:

mkdir -p openwrt-builder
podman run -it -u user -v $(pwd)/openwrt-builder/:/home/user:z,rw quay.io/dpawlik/openwrt:fedora35 /bin/bash

Then inside the container (from https://openwrt.org/docs/guide-developer/toolchain/use-buildsystem):

git clone https://git.openwrt.org/openwrt/openwrt.git
cd openwrt
git pull

Select a specific code revision:

git branch -a
git tag
git checkout v21.02.1

Update the feeds:

./scripts/feeds update -a
./scripts/feeds install -a

Configure the firmware image and the kernel:

make menuconfig

If you have own config file, replace it. For example:

curl -SL https://downloads.openwrt.org/snapshots/targets/ath79/mikrotik/config.buildinfo > .config

Then:

# make kernel_menuconfig
make -j4 kernel_menuconfig

Build the firmware image:

make -j $(nproc) defconfig download clean world