build: add workflow to bootstrap eve-alpine-base on demand

Add a workflow_dispatch workflow that builds and pushes the
eve-alpine-base image for all three platforms (amd64, arm64, riscv64).
This is needed because alpine-base is a bootstrap image that is built
rarely and manually — it is not part of the regular CI build.

The current eve-alpine-base image is missing riscv64, which was lost
during the Alpine 3.22 migration. This workflow allows rebuilding it
without manual Docker access.

Signed-off-by: Mikhail Malyshev <mike.malyshev@gmail.com>

Author: rucoder

.github/workflows/build-alpine-base.yml

@@ -0,0 +1,70 @@
+# Copyright (c) 2026, Zededa, Inc.
+# SPDX-License-Identifier: Apache-2.0
+---
+name: Alpine base image - build and publish on demand
+on:  # yamllint disable-line rule:truthy
+  workflow_dispatch:
+
+permissions: {}
+
+concurrency:
+  group: ${{ github.workflow }}
+  cancel-in-progress: true
+
+jobs:
+  build:
+    # Only run for the default branch
+    if: github.ref_name == github.event.repository.default_branch
+    permissions:
+      contents: read
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - arch: amd64
+            runner: zededa-ubuntu-2204
+          - arch: arm64
+            runner: zededa-ubuntu-2204-arm64
+          - arch: riscv64
+            runner: zededa-ubuntu-2204
+    runs-on: ${{ matrix.runner }}
+
+    steps:
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd  # v6.0.2
+        with:
+          fetch-depth: 0
+          persist-credentials: false
+      - name: Set up QEMU for cross-arch builds
+        if: matrix.arch == 'riscv64'
+        run: |
+          APT_INSTALL="sudo apt install -y binfmt-support qemu-user-static"
+          $APT_INSTALL || { sudo apt update && $APT_INSTALL ; }
+      - name: Login to Docker Hub
+        uses: docker/login-action@b45d80f862d83dbcd57f89517bcf500b2ab88fb2  # v4.0.0
+        with:
+          username: ${{ secrets.RELEASE_DOCKERHUB_ACCOUNT }}
+          password: ${{ secrets.RELEASE_DOCKERHUB_TOKEN }}
+      - name: Build and push alpine-base (${{ matrix.arch }})
+        run: |
+          make V=1 ZARCH=${{ matrix.arch }} LINUXKIT_PKG_TARGET=push pkg/alpine-base
+
+  manifest:
+    needs: build
+    if: github.ref_name == github.event.repository.default_branch
+    runs-on: zededa-ubuntu-2204
+    permissions:
+      contents: read
+
+    steps:
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd  # v6.0.2
+        with:
+          fetch-depth: 0
+          persist-credentials: false
+      - name: Login to Docker Hub
+        uses: docker/login-action@b45d80f862d83dbcd57f89517bcf500b2ab88fb2  # v4.0.0
+        with:
+          username: ${{ secrets.RELEASE_DOCKERHUB_ACCOUNT }}
+          password: ${{ secrets.RELEASE_DOCKERHUB_TOKEN }}
+      - name: Create multi-arch manifest
+        run: |
+          make V=1 LINUXKIT_PKG_TARGET=manifest pkg/alpine-base

pkg/alpine/Dockerfile

@@ -1,6 +1,6 @@
 # DON'T FORGET TO UPDATE THE HASH WHEN SOMETHING CHANGES!
 # please see https://github.com/lf-edge/eve/blob/master/docs/BUILD.md#how-to-update-eve-alpine-package
-FROM lfedge/eve-alpine-base:17217d430af556ba0ddfb6a938c3b3ef93c9b512 AS cache-build
+FROM lfedge/eve-alpine-base:77cc1495c875b7468dbf4123210abf86a1ffb852 AS cache-build
 
 ARG ALPINE_VERSION=3.22
 # this is only needed once, when this package
@@ -40,7 +40,7 @@ done
 RUN cp /mirror/${ALPINE_VERSION}/rootfs/etc/apk/repositories /etc/apk
 RUN apk update
 
-FROM lfedge/eve-alpine-base:17217d430af556ba0ddfb6a938c3b3ef93c9b512 AS compactor
+FROM lfedge/eve-alpine-base:77cc1495c875b7468dbf4123210abf86a1ffb852 AS compactor
 ARG TARGETARCH
 ARG GO_VERSION=1.24.6