diff --git a/Dockerfile.shared-ols b/Dockerfile.shared-ols
index 074497d..fea15f6 100644
--- a/Dockerfile.shared-ols
+++ b/Dockerfile.shared-ols
@@ -24,9 +24,13 @@ FROM litespeedtech/openlitespeed:${OLS_VERSION}-lsphp${PHPVER}
 ##   - gettext-base: envsubst for render-shared-ols-config.sh
 ##   - openssl: self-signed cert for the :443 listener (HAProxy verifies none)
 ##   - curl/ca-certificates: HEALTHCHECK
+##   - procps: provides pgrep, which entrypoint-shared-ols.sh's ols_running()
+##     liveness check depends on. Only transitively present via the base image
+##     today (Ubuntu 24.04 pulls it in) — pin it explicitly so it can't be
+##     pruned as "unused" and silently break the supervisor's crash detection.
 RUN apt-get update && \
     DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends \
-        inotify-tools gettext-base openssl ca-certificates curl && \
+        inotify-tools gettext-base openssl ca-certificates curl procps && \
     apt-get clean && \
     rm -rf /var/lib/apt/lists/* /var/cache/apt/archives/*