From 21118fc9623b4c28cf55aa2516cbf9413879cbff Mon Sep 17 00:00:00 2001
From: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>
Date: Wed, 6 Sep 2023 04:13:17 +0900
Subject: [PATCH] Makefile: add check-preflight

Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>
---
 Makefile                      |  9 ++++-
 Makefile.d/check-preflight.sh | 66 +++++++++++++++++++++++++++++++++++
 2 files changed, 74 insertions(+), 1 deletion(-)
 create mode 100755 Makefile.d/check-preflight.sh

diff --git a/Makefile b/Makefile
index cfd582a..19a15ba 100644
--- a/Makefile
+++ b/Makefile
@@ -18,6 +18,9 @@ export U7S_NODE_NAME:= $(NODE_NAME)
 export U7S_NODE_SUBNET := $(NODE_SUBNET)
 
 DOCKER ?= docker
+
+export DOCKER := $(DOCKER)
+
 COMPOSE := $(DOCKER) compose
 NODE_SERVICE_NAME := node
 NODE_SHELL := $(COMPOSE) exec \
@@ -49,8 +52,12 @@ help:
 	@echo 'make down-v'
 	@echo 'kubectl taint nodes --all node-role.kubernetes.io/control-plane-'
 
+.PHONY: check-preflight
+check-preflight:
+	./Makefile.d/check-preflight.sh
+
 .PHONY: up
-up:
+up: check-preflight
 	$(COMPOSE) up --build -d
 
 .PHONY: down
diff --git a/Makefile.d/check-preflight.sh b/Makefile.d/check-preflight.sh
new file mode 100755
index 0000000..3978498
--- /dev/null
+++ b/Makefile.d/check-preflight.sh
@@ -0,0 +1,66 @@
+#!/bin/bash
+set -eu
+
+function WARNING() {
+	echo >&2 -e "\e[101m\e[97m[WARNING]\e[49m\e[39m $@"
+}
+
+function ERROR() {
+	echo >&2 -e "\e[101m\e[97m[ERROR]\e[49m\e[39m $@"
+}
+
+: "${DOCKER:=docker}"
+
+# Check hard dependency commands
+for f in make jq "${DOCKER}"; do
+	if ! command -v "${f}" >/dev/null 2>&1; then
+		ERROR "Command \"${f}\" is not installed"
+		exit 1
+	fi
+done
+
+# Check soft dependency commands
+for f in kubectl; do
+	if ! command -v "${f}" >/dev/null 2>&1; then
+		WARNING "Command \"${f}\" is not installed"
+	fi
+done
+
+# Check if Docker is running in Rootless mode
+# TODO: support Podman?
+if "${DOCKER}" info --format '{{json .SecurityOptions}}' | grep -q "name=rootless"; then
+	# Check systemd lingering: https://rootlesscontaine.rs/getting-started/common/login/
+	if command -v loginctl >/dev/null 2>&1; then
+		if [ "$(loginctl list-users --output json | jq ".[] | select(.uid == "${UID}").linger")" != "true" ]; then
+			WARNING 'systemd lingering is not enabled. Run `sudo loginctl enable-linger $(whoami)` to enable it, otherwise Kubernetes will exit on logging out.'
+		fi
+	else
+		WARNING "systemd lingering is not enabled?"
+	fi
+
+	# Check cgroup config
+	if [[ ! -f /sys/fs/cgroup/cgroup.controllers ]]; then
+		ERROR "Needs cgroup v2, see https://rootlesscontaine.rs/getting-started/common/cgroup2/"
+		exit 1
+	else
+		f="/sys/fs/cgroup/user.slice/user-$(id -u).slice/user@$(id -u).service/cgroup.controllers"
+		if [[ ! -f $f ]]; then
+			ERROR "systemd not running? file not found: $f"
+			exit 1
+		fi
+		if ! grep -q cpu "${f}"; then
+			WARNING "cpu controller might not be enabled, you need to configure /etc/systemd/system/user@.service.d , see https://rootlesscontaine.rs/getting-started/common/cgroup2/"
+		elif ! grep -q memory "${f}"; then
+			WARNING "memory controller might not be enabled, you need to configure /etc/systemd/system/user@.service.d , see https://rootlesscontaine.rs/getting-started/common/cgroup2/"
+		fi
+	fi
+else
+	WARNING "Docker does not seem running in Rootless mode"
+fi
+
+# Check kernel modules
+for f in ip6_tables ip6table_nat ip_tables iptable_nat vxlan; do
+	if ! grep -qw "^$f" /proc/modules; then
+		WARNING "Kernel module \"${f}\" does not seem loaded? (negligible if built-in to the kernel)"
+	fi
+done