From 8b5821fdedf11694b3bcea81e302c22231d62b89 Mon Sep 17 00:00:00 2001
From: Eguzki Astiz Lezaun <eastizle@redhat.com>
Date: Tue, 26 Sep 2023 15:07:17 +0200
Subject: [PATCH 1/3] [cli] detect number of available CPU shares from cgroups
 v2

---
 gateway/src/apicast/cli/environment.lua | 38 ++++++++++++++++++++-----
 1 file changed, 31 insertions(+), 7 deletions(-)

diff --git a/gateway/src/apicast/cli/environment.lua b/gateway/src/apicast/cli/environment.lua
index b208ba152..fe6292e42 100644
--- a/gateway/src/apicast/cli/environment.lua
+++ b/gateway/src/apicast/cli/environment.lua
@@ -51,16 +51,35 @@ local function detect_kubernetes()
   return secrets or resty_env.value('KUBERNETES_PORT')
 end
 
+-- CPU shares in Cgroups v1 or converted from weight in Cgroups v2 in millicores
 local function cpu_shares()
-  if not detect_kubernetes() then return end
-
   local shares
-  local file = open('/sys/fs/cgroup/cpu/cpu.shares')
 
-  if file then
-    shares = file:read('*n')
+  -- This check is from https://github.com/kubernetes/kubernetes/blob/release-1.27/test/e2e/node/pod_resize.go#L305-L314
+  -- alternatively, this method can be used: https://kubernetes.io/docs/concepts/architecture/cgroups/#check-cgroup-version
+  -- (`stat -fc %T /sys/fs/cgroup/` returns `cgroup2fs` or `tmpfs`)
+  if pl_path.exists("/sys/fs/cgroup/cgroup.controllers") then
+    -- Cgroups v2
+    ngx.log(ngx.DEBUG, "detecting cpus in Cgroups v2")
+    -- Using the formula from https://github.com/kubernetes/kubernetes/blob/release-1.27/pkg/kubelet/cm/cgroup_manager_linux.go#L570-L574
+    local file = open('/sys/fs/cgroup/cpu.weight')
+
+    if file then
+      local weight = file:read('*n')
+      shares = (((weight - 1) * 262142) / 9999) + 2
+
+      file:close()
+    end
+  else
+    -- Cgroups v1
+    ngx.log(ngx.DEBUG, "detecting cpus in Cgroups v1")
+    local file = open('/sys/fs/cgroup/cpu/cpu.shares')
 
-    file:close()
+    if file then
+      shares = file:read('*n')
+
+      file:close()
+    end
   end
 
   return shares
@@ -68,11 +87,16 @@ end
 
 local function cpus()
     local shares = cpu_shares()
-    if shares then return ceil(shares / 1024) end
+    if shares then
+      local res = ceil(shares / 1024)
+      ngx.log(ngx.DEBUG, "cpu_shares = "..res)
+      return res
+    end
 
     -- TODO: support /sys/fs/cgroup/cpuset/cpuset.cpus
     -- see https://github.com/sclorg/rhscl-dockerfiles/blob/ff912d8764af9a41096e63064bbc325395afa608/rhel7.sti-base/bin/cgroup-limits#L55-L75
     local nproc = util.system('nproc')
+    ngx.log(ngx.DEBUG, "cpus from nproc = "..nproc)
     return tonumber(nproc)
 end
 

From 5c99dfdec4ef75b465ef917ec9c24e558e48e6f7 Mon Sep 17 00:00:00 2001
From: Eguzki Astiz Lezaun <eastizle@redhat.com>
Date: Tue, 26 Sep 2023 15:52:27 +0200
Subject: [PATCH 2/3] CHANGELOG.md: add entry

---
 CHANGELOG.md | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8b7d0157c..76bc30dd5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,12 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [Unreleased]
 
+### Added
+
+- Detect number of CPU shares when running on Cgroups V2 [PR #1410](https://github.com/3scale/apicast/pull/1410) [THREESCALE-10167](https://issues.redhat.com/browse/THREESCALE-10167)
+
+## [3.14.0] 2023-07-25
+
 ### Fixed
 
 - In boot mode on `init_worker` check configuration expiration [PR #1399](https://github.com/3scale/APIcast/pull/1399) [THREESCALE-9003](https://issues.redhat.com/browse/THREESCALE-9003)

From 39e9f2c3c8c10222f649dfbe4609f5b9ed3cc7d9 Mon Sep 17 00:00:00 2001
From: Eguzki Astiz Lezaun <eastizle@redhat.com>
Date: Tue, 26 Sep 2023 17:18:10 +0200
Subject: [PATCH 3/3] cpu detection: early closing of file pointer

---
 gateway/src/apicast/cli/environment.lua | 12 ++----------
 1 file changed, 2 insertions(+), 10 deletions(-)

diff --git a/gateway/src/apicast/cli/environment.lua b/gateway/src/apicast/cli/environment.lua
index fe6292e42..4b201f28a 100644
--- a/gateway/src/apicast/cli/environment.lua
+++ b/gateway/src/apicast/cli/environment.lua
@@ -43,14 +43,6 @@ local function parse_nameservers()
     end
 end
 
-local function detect_kubernetes()
-  local secrets = open('/run/secrets/kubernetes.io')
-
-  if secrets then secrets:close() end
-
-  return secrets or resty_env.value('KUBERNETES_PORT')
-end
-
 -- CPU shares in Cgroups v1 or converted from weight in Cgroups v2 in millicores
 local function cpu_shares()
   local shares
@@ -66,9 +58,9 @@ local function cpu_shares()
 
     if file then
       local weight = file:read('*n')
-      shares = (((weight - 1) * 262142) / 9999) + 2
-
       file:close()
+
+      shares = (((weight - 1) * 262142) / 9999) + 2
     end
   else
     -- Cgroups v1