diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index ea3356f..62bcb51 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -9,7 +9,6 @@ on:
       - main
 jobs:
   example:
-    environment: integration
     strategy:
       fail-fast: false
       matrix:
@@ -28,11 +27,11 @@ jobs:
     runs-on: ${{matrix.os}}
     env:
       ADVERTISED_LISTENER_URL: tcp://nisshi:9092
-      AWS_ACCESS_KEY_ID: ${{ secrets.AWS_ACCESS_KEY_ID }}
+      AWS_ACCESS_KEY_ID: minioadmin
       AWS_ALLOW_HTTP: true
       AWS_DEFAULT_REGION: auto
       AWS_ENDPOINT: http://minio:9000
-      AWS_SECRET_ACCESS_KEY: ${{ secrets.AWS_SECRET_ACCESS_KEY }}
+      AWS_SECRET_ACCESS_KEY: minioadmin
       CLUSTER_ID: kafka-python-integration
       KAFKA_IMAGE: ${{matrix.kafka}}
       PROMETHEUS_LISTENER_URL: tcp://localhost:9100
@@ -44,7 +43,7 @@ jobs:
       - uses: actions/checkout@v4
       - run: docker compose --ansi never --progress plain up --no-color --quiet-pull --detach
       - run: docker compose --ansi never exec minio /usr/bin/mc ready local
-      - run: docker compose --ansi never exec minio /usr/bin/mc alias set local http://localhost:9000 ${{ secrets.AWS_ACCESS_KEY_ID }} ${{ secrets.AWS_SECRET_ACCESS_KEY }}
+      - run: docker compose --ansi never exec minio /usr/bin/mc alias set local http://localhost:9000 minioadmin minioadmin
       - run: docker compose --ansi never exec minio /usr/bin/mc mb local/nisshi
       - run: sudo apt-get update
       - run: sudo apt-get install -y bats
diff --git a/compose.yaml b/compose.yaml
index d6f4e01..a9c26b0 100644
--- a/compose.yaml
+++ b/compose.yaml
@@ -17,7 +17,7 @@ services:
       retries: 5
     pull_policy: missing
   minio:
-    image: quay.io/minio/minio
+    build: etc/minio
     command: server /data --console-address ":9001"
     volumes:
       - minio:/data
diff --git a/etc/minio/Dockerfile b/etc/minio/Dockerfile
new file mode 100644
index 0000000..445147f
--- /dev/null
+++ b/etc/minio/Dockerfile
@@ -0,0 +1,40 @@
+# MinIO no longer distributes prebuilt binaries or container images for
+# anonymous/public use: dl.min.io returns 410 Gone, Docker Hub's minio/minio
+# repository is gone, and third-party mirrors (e.g. Chainguard's free-tier
+# rebuild) are subject to their own registry limits and terms, unrelated to
+# MinIO's. Both the server (minio) and client (mc) stay public because
+# they're AGPLv3-licensed, so this builds both ourselves from that source
+# instead of depending on any registry's redistribution of them. mc is
+# required too: justfile's minio-mc/minio-ready-local/etc. recipes and CI
+# run it via `docker compose exec minio /usr/bin/mc ...` - it's expected
+# inside this same container, matching upstream's own image layout.
+#
+# Both pinned to the last tagged release on their (now archived,
+# read-only) upstream repos - each has a few untagged commits after this,
+# but nothing past an official release has been vetted as one.
+FROM golang:1.24-alpine AS build
+RUN apk add --no-cache git
+
+ARG MINIO_VERSION=RELEASE.2025-10-15T17-29-55Z
+WORKDIR /src/minio
+RUN git clone --depth 1 --branch ${MINIO_VERSION} https://github.com/minio/minio.git .
+RUN --mount=type=cache,target=/root/.cache/go-build \
+    --mount=type=cache,target=/go/pkg/mod \
+    CGO_ENABLED=0 go build -trimpath \
+      -ldflags "-X github.com/minio/minio/cmd.Version=${MINIO_VERSION} -X github.com/minio/minio/cmd.ReleaseTag=${MINIO_VERSION}" \
+      -o /out/minio .
+
+ARG MC_VERSION=RELEASE.2025-08-13T08-35-41Z
+WORKDIR /src/mc
+RUN git clone --depth 1 --branch ${MC_VERSION} https://github.com/minio/mc.git .
+RUN --mount=type=cache,target=/root/.cache/go-build \
+    --mount=type=cache,target=/go/pkg/mod \
+    CGO_ENABLED=0 go build -trimpath \
+      -ldflags "-X github.com/minio/mc/cmd.Version=${MC_VERSION} -X github.com/minio/mc/cmd.ReleaseTag=${MC_VERSION}" \
+      -o /out/mc .
+
+FROM alpine:3.20
+# bash is required by compose.yaml's healthcheck (runs inside this container).
+RUN apk add --no-cache ca-certificates bash
+COPY --from=build /out/minio /out/mc /usr/bin/
+ENTRYPOINT ["/usr/bin/minio"]