mon: add an "osd crush tree" command

* to print crush buckets/items in a tree

Fixes: #11833
Signed-off-by: Kefu Chai <kchai@redhat.com>
(cherry picked from commit 5436c29)

Conflicts:
	src/test/mon/osd-crush.sh:
		do not start mon as run() takes care of it already

doc/man/8/ceph.rst

@@ -669,6 +669,12 @@ Usage::
 
 	ceph osd crush show-tunables
 
+Subcommand ``tree`` shows the crush buckets and items in a tree view.
+
+Usage::
+
+	ceph osd crush tree
+
 Subcommand ``tunables`` sets crush tunables values to <profile>.
 
 Usage::

src/crush/CrushWrapper.cc

@@ -1409,6 +1409,56 @@ void CrushWrapper::dump(Formatter *f) const
   f->close_section();
 }
 
+namespace {
+  // depth first walker
+  class TreeDumper {
+    typedef CrushTreeDumper::Item Item;
+    const CrushWrapper *crush;
+  public:
+    TreeDumper(const CrushWrapper *crush)
+      : crush(crush) {}
+
+    void dump(Formatter *f) {
+      set<int> roots;
+      crush->find_roots(roots);
+      for (set<int>::iterator root = roots.begin(); root != roots.end(); ++root) {
+	dump_item(Item(*root, 0, crush->get_bucket_weightf(*root)), f);
+      }
+    }
+
+  private:
+    void dump_item(const Item& qi, Formatter* f) {
+      if (qi.is_bucket()) {
+	f->open_object_section("bucket");
+	CrushTreeDumper::dump_item_fields(crush, qi, f);
+	dump_bucket_children(qi, f);
+	f->close_section();
+      } else {
+	f->open_object_section("device");
+	CrushTreeDumper::dump_item_fields(crush, qi, f);
+	f->close_section();
+      }
+    }
+
+    void dump_bucket_children(const Item& parent, Formatter* f) {
+      f->open_array_section("items");
+      const int max_pos = crush->get_bucket_size(parent.id);
+      for (int pos = 0; pos < max_pos; pos++) {
+	int id = crush->get_bucket_item(parent.id, pos);
+	float weight = crush->get_bucket_item_weightf(parent.id, pos);
+	dump_item(Item(id, parent.depth + 1, weight), f);
+      }
+      f->close_section();
+    }
+  };
+}
+
+void CrushWrapper::dump_tree(Formatter *f) const
+{
+  assert(f);
+  TreeDumper(this).dump(f);
+}
+
 void CrushWrapper::dump_tunables(Formatter *f) const
 {
   f->dump_int("choose_local_tries", get_choose_local_tries());

src/crush/CrushWrapper.h

@@ -1054,6 +1054,7 @@ class CrushWrapper {
   void dump_tunables(Formatter *f) const;
   void list_rules(Formatter *f) const;
   void dump_tree(ostream *out, Formatter *f) const;
+  void dump_tree(Formatter *f) const;
   static void generate_test_instances(list<CrushWrapper*>& o);
 
   int get_osd_pool_default_crush_replicated_ruleset(CephContext *cct);

src/mon/MonCommands.h

@@ -521,6 +521,9 @@ COMMAND("osd crush rule create-erasure " \
 COMMAND("osd crush rule rm " \
 	"name=name,type=CephString,goodchars=[A-Za-z0-9-_.] ",	\
 	"remove crush rule <name>", "osd", "rw", "cli,rest")
+COMMAND("osd crush tree",
+	"dump crush buckets and items in a tree view",
+	"osd", "r", "cli,rest")
 COMMAND("osd setmaxosd " \
 	"name=newmax,type=CephInt,range=0", \
 	"set new maximum osd value", "osd", "rw", "cli,rest")

src/mon/OSDMonitor.cc

@@ -3367,6 +3367,12 @@ bool OSDMonitor::preprocess_command(MMonCommand *m)
     f->flush(rs);
     rs << "\n";
     rdata.append(rs.str());
+  } else if (prefix == "osd crush tree") {
+    boost::scoped_ptr<Formatter> f(Formatter::create(format, "json-pretty", "json-pretty"));
+    f->open_array_section("crush_map_roots");
+    osdmap.crush->dump_tree(f.get());
+    f->close_section();
+    f->flush(rdata);
   } else if (prefix == "osd erasure-code-profile ls") {
     const map<string,map<string,string> > &profiles =
       osdmap.get_erasure_code_profiles();

src/test/mon/osd-crush-tree.rng

@@ -0,0 +1,62 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<grammar xmlns="http://relaxng.org/ns/structure/1.0">
+  <start>
+    <ref name="crush_map_roots"/>
+  </start>
+  <define name="item">
+    <choice>
+      <ref name="bucket"/>
+      <ref name="device"/>
+    </choice>
+  </define>
+  <define name="device">
+    <element name="device">
+      <element name="id">
+        <text/>
+      </element>
+      <element name="name">
+        <text/>
+      </element>
+      <element name="type">
+        <text/>
+      </element>
+      <element name="type_id">
+        <text/>
+      </element>
+      <element name="crush_weight">
+        <text/>
+      </element>
+      <element name="depth">
+        <text/>
+      </element>
+    </element>
+  </define>
+  <define name="bucket">
+    <element name="bucket">
+      <element name="id">
+        <text/>
+      </element>
+      <element name="name">
+        <text/>
+      </element>
+      <element name="type">
+        <text/>
+      </element>
+      <element name="type_id">
+        <text/>
+      </element>
+      <element name="items">
+        <zeroOrMore>
+          <ref name="item"/>
+        </zeroOrMore>
+      </element>
+    </element>
+  </define>
+  <define name="crush_map_roots">
+    <element name="crush_map_roots">
+      <oneOrMore>
+        <ref name="bucket"/>
+      </oneOrMore>
+    </element>
+  </define>
+</grammar>

src/test/mon/osd-crush.sh

@@ -200,7 +200,12 @@ function TEST_crush_reject_empty() {
         ./ceph osd setcrushmap -i $empty_map.map || return 1
 }
 
-main osd-crush
+function TEST_crush_tree() {
+    ./ceph osd crush tree --format=xml | \
+        $XMLSTARLET val -e -r test/mon/osd-crush-tree.rng - || return 1
+}
+
+main osd-crush 
 
 # Local Variables:
 # compile-command: "cd ../.. ; make -j4 && test/mon/osd-crush.sh"