foo:PRIMARY> rs.conf()
{
	"_id" : "foo",
	"version" : 2,
	"members" : [
		{
			"_id" : 0,
			"host" : "erh-mb5-2.local:27017"
		}
	]
}
foo:PRIMARY> x = rs.conf()
{
	"_id" : "foo",
	"version" : 2,
	"members" : [
		{
			"_id" : 0,
			"host" : "erh-mb5-2.local:27017"
		}
	]
}
foo:PRIMARY> x.settings = { chainingAllowed : false }
{ "chainingAllowed" : false }
foo:PRIMARY> x
{
	"_id" : "foo",
	"version" : 2,
	"members" : [
		{
			"_id" : 0,
			"host" : "erh-mb5-2.local:27017"
		}
	],
	"settings" : {
		"chainingAllowed" : false
	}
}
foo:PRIMARY> rs.reconfig(x)
{ "ok" : 1 }
foo:PRIMARY> rs.conf()
{
	"_id" : "foo",
	"version" : 3,
	"members" : [
		{
			"_id" : 0,
			"host" : "erh-mb5-2.local:27017"
		}
	]
}
foo:PRIMARY>