當集羣容量或者計算資源達到一定限定時，就需要對集羣進行擴容，擴容操作主要可以分爲兩種 ：
1、縱向擴展：向已有節點中添加磁盤，容量增加，集羣計算性能不變；
2、橫向擴展：添加新的節點，包括磁盤、內存、cpu資源，可以達到擴容性能提升的效果；
一、 在生產環境中避免新增節點影響性能，添加標識位
生產環境中，一般不會在新節點加入ceph集羣后，立即開始數據回填，這樣會影響集羣性能。所以我們需要設置一些標誌位，來完成這個目的。
[root@node140 ~]##ceph osd set noin
[root@node140 ~]##ceph osd set nobackfill
在用戶訪問的非高峯時，取消這些標誌位，集羣開始在平衡任務。
[root@node140 ~]##ceph osd unset noin
[root@node140 ~]##ceph osd unset nobackfill
二、新節點安裝ceph
（1）#手動yum集羣部署
[root@node143 ~]# yum -y install ceph ceph-radosgw
（2）#檢查安裝的包
[root@node143 ~]# rpm -qa | egrep -i "ceph|rados|rbd"
（3）#檢查ceph 安裝本版，需要統一版本
[root@node143 ~]# ceph -v 全部都是（nautilus版本）
ceph version 14.2.2 (4f8fa0a0024755aae7d95567c63f11d6862d55be) nautilus (stable)
三、向ceph集羣中新增節點
ceph可以無縫擴展，支持在線添加osd和monitor節點
（1）健康集羣
[root@node140 ~]# ceph -s
cluster:
id: 58a12719-a5ed-4f95-b312-6efd6e34e558
health: HEALTH_OK
services:
mon: 2 daemons, quorum node140,node142 (age 8d)
mgr: admin(active, since 8d), standbys: node140
mds: cephfs:1 {0=node140=up:active} 1 up:standby
osd: 16 osds: 16 up (since 5m), 16 in (since 2w)
data:
pools: 5 pools, 768 pgs
objects: 2.65k objects, 9.9 GiB
usage: 47 GiB used, 8.7 TiB / 8.7 TiB avail
pgs: 768 active+clean（2）當前集羣節點數量爲3
[root@node140 ~]# ceph osd tree
ID CLASS WEIGHT TYPE NAME STATUS REWEIGHT PRI-AFF
-1 8.71826 root default
-2 3.26935 host node140
0 hdd 0.54489 osd.0 up 1.00000 1.00000
1 hdd 0.54489 osd.1 up 1.00000 1.00000
2 hdd 0.54489 osd.2 up 1.00000 1.00000
3 hdd 0.54489 osd.3 up 1.00000 1.00000
4 hdd 0.54489 osd.4 up 1.00000 1.00000
5 hdd 0.54489 osd.5 up 1.00000 1.00000
-3 3.26935 host node141
12 hdd 0.54489 osd.12 up 1.00000 1.00000
13 hdd 0.54489 osd.13 up 1.00000 1.00000
14 hdd 0.54489 osd.14 up 1.00000 1.00000
15 hdd 0.54489 osd.15 up 1.00000 1.00000
16 hdd 0.54489 osd.16 up 1.00000 1.00000
17 hdd 0.54489 osd.17 up 1.00000 1.00000
-4 2.17957 host node142
6 hdd 0.54489 osd.6 up 1.00000 1.00000
9 hdd 0.54489 osd.9 up 1.00000 1.00000
10 hdd 0.54489 osd.10 up 1.00000 1.00000
11 hdd 0.54489 osd.11 up 1.00000 1.00000 （3）集羣節點複製配置文件和密鑰到新增節點node143
[root@node143 ceph]# ls
ceph.client.admin.keyring ceph.conf（4）新增節點具備訪問集羣權限
[root@node143 ceph]# ceph -s
cluster:
id: 58a12719-a5ed-4f95-b312-6efd6e34e558
health: HEALTH_OK
services:
mon: 2 daemons, quorum node140,node142 (age 8d)
mgr: admin(active, since 8d), standbys: node140
mds: cephfs:1 {0=node140=up:active} 1 up:standby
osd: 16 osds: 16 up (since 25m), 16 in (since 2w)
data:
pools: 5 pools, 768 pgs
objects: 2.65k objects, 9.9 GiB
usage: 47 GiB used, 8.7 TiB / 8.7 TiB avail
pgs: 768 active+clean（5）準備好磁盤
[root@node143 ceph]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 557.9G 0 disk
├─sda1 8:1 0 200M 0 part /boot
└─sda2 8:2 0 519.4G 0 part
└─centos-root 253:0 0 519.4G 0 lvm /
sdb 8:16 0 558.9G 0 disk
sdc 8:32 0 558.9G 0 disk
sdd 8:48 0 558.9G 0 disk
sde 8:64 0 558.9G 0 disk
sdf 8:80 0 558.9G 0 disk
sdg 8:96 0 558.9G 0 disk （6）#將作爲osd磁盤標記爲GPT格式
[root@node143 ]# parted /dev/sdc mklabel GPT
[root@node143 ]# parted /dev/sdd mklabel GPT
[root@node143 ]# parted /dev/sdf mklabel GPT
[root@node143 ]#parted /dev/sdg mklabel GPT
[root@node143 ]# parted /dev/sdb mklabel GPT
[root@node143 ]# parted /dev/sde mklabel GPT（7）#格式化成爲xfs文件系統
[root@node143 ]# mkfs.xfs -f /dev/sdc
[root@node143 ]# mkfs.xfs -f /dev/sdd
[root@node143 ]# mkfs.xfs -f /dev/sdb
[root@node143 ]# mkfs.xfs -f /dev/sdf
[root@node143 ]# mkfs.xfs -f /dev/sdg
[root@node143 ]# mkfs.xfs -f /dev/sde（8）創建osd
[root@node143 ~]# ceph-volume lvm create --data /dev/sdb
--> ceph-volume lvm activate successful for osd ID: 0
--> ceph-volume lvm create successful for: /dev/sdb
[root@node143 ~]# ceph-volume lvm create --data /dev/sdc
[root@node143 ~]# ceph-volume lvm create --data /dev/sdd
[root@node143 ~]# ceph-volume lvm create --data /dev/sdf
[root@node143 ~]# ceph-volume lvm create --data /dev/sdg
[root@node143 ~]# ceph-volume lvm create --data /dev/sde[root@node143 ~]# blkid
/dev/mapper/centos-root: UUID="7616a088-d812-456b-8ae8-38d600eb9f8b" TYPE="xfs"
/dev/sda2: UUID="6V8bFT-ylA6-bifK-gmob-ah3I-zZ4G-N7EYwD" TYPE="LVM2_member"
/dev/sda1: UUID="eee4c9af-9f12-44d9-a386-535bde734678" TYPE="xfs"
/dev/sdb: UUID="TcjeCg-YsBQ-RHbm-UNYT-UoQv-iLFs-f1st2X" TYPE="LVM2_member"
/dev/sdd: UUID="aSLPmt-ohdJ-kG7W-JOB1-dzOD-D0zp-krWW5m" TYPE="LVM2_member"
/dev/sdc: UUID="7ARhbT-S9sC-OdZw-kUCq-yp97-gSpY-hfoPFa" TYPE="LVM2_member"
/dev/sdg: UUID="9MDhh1-bXIX-DwVf-RkIt-IUVm-fPEH-KSbsDd" TYPE="LVM2_member"
/dev/sde: UUID="oc2gSZ-j3WO-pOUs-qJk6-ZZS0-R8V7-1vYaZv" TYPE="LVM2_member"
/dev/sdf: UUID="jxQjNS-8xpV-Hc4p-d2Vd-1Q8O-U5Yp-j1Dn22" TYPE="LVM2_member" （9）#查看創建osd
[root@node143 ~]# ceph-volume lvm list
[root@node143 ~]# lsblk
（10）#OSD會自動啓動
[root@node143 ~]# ceph osd tree
ID CLASS WEIGHT TYPE NAME STATUS REWEIGHT PRI-AFF
-1 11.98761 root default
-2 3.26935 host node140
0 hdd 0.54489 osd.0 up 1.00000 1.00000
1 hdd 0.54489 osd.1 up 1.00000 1.00000
2 hdd 0.54489 osd.2 up 1.00000 1.00000
3 hdd 0.54489 osd.3 up 1.00000 1.00000
4 hdd 0.54489 osd.4 up 1.00000 1.00000
5 hdd 0.54489 osd.5 up 1.00000 1.00000
-3 3.26935 host node141
12 hdd 0.54489 osd.12 up 1.00000 1.00000
13 hdd 0.54489 osd.13 up 1.00000 1.00000
14 hdd 0.54489 osd.14 up 1.00000 1.00000
15 hdd 0.54489 osd.15 up 1.00000 1.00000
16 hdd 0.54489 osd.16 up 1.00000 1.00000
17 hdd 0.54489 osd.17 up 1.00000 1.00000
-4 2.17957 host node142
6 hdd 0.54489 osd.6 up 1.00000 1.00000
9 hdd 0.54489 osd.9 up 1.00000 1.00000
10 hdd 0.54489 osd.10 up 1.00000 1.00000
11 hdd 0.54489 osd.11 up 1.00000 1.00000
-9 3.26935 host node143
7 hdd 0.54489 osd.7 up 1.00000 1.00000
8 hdd 0.54489 osd.8 up 1.00000 1.00000
18 hdd 0.54489 osd.18 up 0 1.00000
19 hdd 0.54489 osd.19 up 0 1.00000
20 hdd 0.54489 osd.20 up 0 1.00000
21 hdd 0.54489 osd.21 up 0 1.00000 ====== osd.0 =======
顯示osd.num，num後面會用到。
[root@node143 ~]# systemctl enable ceph-osd@7
[root@node143 ~]# systemctl enable ceph-osd@8
[root@node143 ~]# systemctl enable ceph-osd@18
[root@node143 ~]# systemctl enable ceph-osd@19
[root@node143 ~]# systemctl enable ceph-osd@20
[root@node143 ~]# systemctl enable ceph-osd@21（11）查看集羣，擴容成功
[root@node143 ~]# ceph -s
cluster:
id: 58a12719-a5ed-4f95-b312-6efd6e34e558
health: HEALTH_WARN
noin,nobackfill flag(s) set
services:
mon: 2 daemons, quorum node140,node142 (age 8d)
mgr: admin(active, since 8d), standbys: node140
mds: cephfs:1 {0=node140=up:active} 1 up:standby
osd: 22 osds: 22 up (since 4m), 18 in (since 9m); 2 remapped pgs
flags noin,nobackfill
data:
pools: 5 pools, 768 pgs
objects: 2.65k objects, 9.9 GiB
usage: 54 GiB used, 12 TiB / 12 TiB avail
pgs: 766 active+clean
1 active+remapped+backfilling
1 active+remapped+backfill_wait（12）記得低峯時段取消標誌位
在用戶訪問的非高峯時，取消這些標誌位，集羣開始在平衡任務。
[root@node140 ~]##ceph osd unset noin
[root@node140 ~]##ceph osd unset nobackfill