轉自：hive的hiveserver2模式啟動不起來，發現Hadoop一直處於安全模式 - -小魚- - 博客園 (cnblogs.com)
hadoop去掉保護模式
命令hadoop fs –safemode get 查看安全模式狀態
命令hadoop fs –safemode enter 進入安全模式狀態
命令hadoop fs –safemode leave 離開安全模式狀態
hdfs dfsadmin -safemode leave
第一步：用hadoop fsck 檢查hadoop文件系統
命令：Hadoop fsck
1 hadoop fsck 2 3 Usage: DFSck <path> [-move | -delete | -openforwrite] [-files [-blocks [-locations | -racks]]] 4 <path> 檢查這個目錄中的文件是否完整 5 6 -move 破損的文件移至/lost+found目錄 7 -delete 刪除破損的文件 8 9 -openforwrite 打印正在打開寫操作的文件 10 11 -files 打印正在check的文件名 12 13 -blocks 打印block報告 （需要和-files參數一起使用） 14 15 -locations 打印每個block的位置信息（需要和-files參數一起使用） 16 17 -racks 打印位置信息的網絡拓撲圖 （需要和-files參數一起使用）
觀察hadoop集群狀態
CORRUPT FILES: 2 #損壞了兩個文件
MISSING BLOCKS: 2 #丟失了兩個塊
1 Status: CORRUPT 2 Number of data-nodes: 1 3 Number of racks: 1 4 Total dirs: 72 5 Total symlinks: 0 6 7 Replicated Blocks: 8 Total size: 574348338 B 9 Total files: 76 10 Total blocks (validated): 74 (avg. block size 7761464 B) 11 ******************************** 12 UNDER MIN REPL'D BLOCKS: 35 (47.2973 %) 13 MINIMAL BLOCK REPLICATION: 1 14 CORRUPT FILES: 35 15 MISSING BLOCKS: 35 16 MISSING SIZE: 327840971 B 17 ******************************** 18 Minimally replicated blocks: 39 (52.7027 %) 19 Over-replicated blocks: 0 (0.0 %) 20 Under-replicated blocks: 38 (51.351353 %) 21 Mis-replicated blocks: 0 (0.0 %) 22 Default replication factor: 3 23 Average block replication: 0.527027 24 Missing blocks: 35 25 Corrupt blocks: 0 26 Missing replicas: 160 (38.46154 %) 27 28 Erasure Coded Block Groups: 29 Total size: 0 B 30 Total files: 0 31 Total block groups (validated): 0 32 Minimally erasure-coded block groups: 0 33 Over-erasure-coded block groups: 0 34 Under-erasure-coded block groups: 0 35 Unsatisfactory placement block groups: 0 36 Average block group size: 0.0 37 Missing block groups: 0 38 Corrupt block groups: 0 39 Missing internal blocks: 0 40 FSCK ended at Wed Jan 12 20:13:16 CST 2022 in 28 milliseconds
第二步 打印hadoop文件的狀態信息
命令：hadoop fsck / -files -blocks -locations -racks
可以看到正常文件后面都有ok字樣，有MISSING!字樣的就是丟失的文件。
/tmp/hadoop-yarn/staging/history/done_intermediate/root/job_1641978125772_0001_conf.xml_tmp 0 bytes, replicated: replication=3, 0 block(s): OK
/tmp/hadoop-yarn/staging/root/.staging/job_1641780921957_0001/job.split 315 bytes, replicated: replication=10, 1 block(s): MISSING 1 blocks of total size 315 B
根據這個的路勁可以在hadoop瀏覽器界面中找到對應的文件路徑，如下圖
hadoop fs -chmod -R 777 /tmp
第三步：修復兩個丟失、損壞的文件
[root@node03 conf]# hdfs debug recoverLease -path /flink-checkpoint/626ea65de810a2ec3b1799b605a6a995/chk-175/19195239-a205-4462-921d-09e0483a4080 -retries 10
[root@node03 conf]# hdfs debug recoverLease -path /flink-checkpoint/626ea65de810a2ec3b1799b605a6a995/chk-175/_metadata -retries 10
..Status: HEALTHY 集群狀態：健康
現在重新啟動hadoop就不會一直處於安全模式了，hiveserver2也能正常啟動了。。
第四：意外狀況
.............Status: CORRUPT #Hadoop狀態：不正常 Total size: 273821489 B Total dirs: 403 Total files: 213 Total symlinks: 0 Total blocks (validated): 201 (avg. block size 1362295 B) ******************************** UNDER MIN REPL'D BLOCKS: 2 (0.99502486 %) dfs.namenode.replication.min: 1 CORRUPT FILES: 2 #損壞了兩個文件 MISSING BLOCKS: 2 #丟失了兩個塊 MISSING SIZE: 6174 B CORRUPT BLOCKS: 2 ******************************** Minimally replicated blocks: 199 (99.004974 %) Over-replicated blocks: 0 (0.0 %) Under-replicated blocks: 0 (0.0 %) Mis-replicated blocks: 0 (0.0 %) Default replication factor: 3 Average block replication: 2.8208954 Corrupt blocks: 2 Missing replicas: 0 (0.0 %) Number of data-nodes: 3 Number of racks: 1 FSCK ended at Fri Aug 23 10:43:11 CST 2019 in 12 milliseconds 1、如果損壞的文件不重要
首先：將找到的損壞文件備份好
然后：執行[root@node03 export]# hadoop fsck / -delete將損壞文件刪除
[root@node03 export]# hadoop fsck / -delete 此命令一次不成功可以多試幾次，前提是丟失、損壞的文件不重要！！！！！！！！！！
2、如果損壞的文件很重要不能丟失
可以先執行此命令：hadoop fs –safemode leave 強制離開安全模式狀態
[root@node03 export]# hadoop fs –safemode leave 此操作不能完全解決問題，只能暫時讓集群能夠工作！！！！
而且，以后每次啟動hadoop集群都要執行此命令，直到問題徹底解決。
如果並非以上問題請轉這篇：
https://www.cnblogs.com/-xiaoyu-/p/12158984.html