From 259987596d316df1740f12941309ccc49ea4261b Mon Sep 17 00:00:00 2001
From: CrazyMax <crazy-max@users.noreply.github.com>
Date: Wed, 16 Feb 2022 22:32:09 +0100
Subject: [PATCH] docs: custom image with cni networking

Signed-off-by: CrazyMax <crazy-max@users.noreply.github.com>
---
 docs/cni-networking.md | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)
 create mode 100644 docs/cni-networking.md

diff --git a/docs/cni-networking.md b/docs/cni-networking.md
new file mode 100644
index 00000000..9a890867
--- /dev/null
+++ b/docs/cni-networking.md
@@ -0,0 +1,30 @@
+# CNI networking
+
+It can be useful to use a bridge network for your builder if for example you
+encounter a network port contention during multiple builds. If you're using
+the BuildKit image, CNI is not [(yet)](https://github.com/moby/buildkit/issues/28)
+available in it.
+
+But you can create your own BuildKit image with CNI support:
+
+```dockerfile
+ARG BUILDKIT_VERSION=v0.9.3
+ARG CNI_VERSION=v1.0.1
+
+FROM --platform=$BUILDPLATFORM alpine AS cni-plugins
+RUN apk add --no-cache curl
+ARG CNI_VERSION
+ARG TARGETOS
+ARG TARGETARCH
+WORKDIR /opt/cni/bin
+RUN curl -Ls https://github.com/containernetworking/plugins/releases/download/$CNI_VERSION/cni-plugins-$TARGETOS-$TARGETARCH-$CNI_VERSION.tgz | tar xzv
+
+FROM moby/buildkit:${BUILDKIT_VERSION}
+ARG BUILDKIT_VERSION
+RUN apk add --no-cache iptables
+COPY --from=cni-plugins /opt/cni/bin /opt/cni/bin
+ADD https://raw.githubusercontent.com/moby/buildkit/${BUILDKIT_VERSION}/hack/fixtures/cni.json /etc/buildkit/cni.json
+```
+
+Here we use the [CNI config for integration tests in BuildKit](../hack/fixtures/cni.json),
+but feel free to use your own config.