fix: change iptables backend to legacy (#57)

* fix: change `iptables` backend to legacy

* ci: bump version

* docs: document chnges

* fix: change `ip6tables` backend to legacy

* docs: improve documentation

* docs: improve documentation

Dockerfile

@@ -28,8 +28,14 @@ RUN echo 'http://dl-cdn.alpinelinux.org/alpine/v3.19/main' >> /etc/apk/repositor
   && apk upgrade \
   # Add fuse-overlayfs for comaptibility with rootless. Volumes created with rootless might use fuse-overlay formatted volumes. If those volumes are later used by dind that runs with root it'll require fuse-overlay to be able to read the volume
   && apk add bash fuse-overlayfs jq --no-cache \
+  # Needed only for `update-alternatives` below
+  && apk add dpkg --no-cache \
   && rm -rf /var/cache/apk/*
 
+# Backward compatibility with kernels that do not support `iptables-nft`. Check #CR-23033 for details.
+RUN update-alternatives --install $(which iptables) iptables $(which iptables-legacy) 10 \
+  && update-alternatives --install $(which ip6tables) ip6tables $(which ip6tables-legacy) 10
+
 COPY --from=node-exporter /bin/node_exporter /bin/
 COPY --from=cleaner /usr/local/bin/dind-cleaner /bin/
 COPY --from=bbolt /go/bin/bbolt /bin/

service.yaml

@@ -1 +1 @@
-version: 1.28.4
+version: 1.28.5