CentOS7 SELinux阻止MongoDB啟動的問題__Linux

問題描述：

在新裝的CentOS7上，安裝了MongoDB3.4，掛載了一個大的資料盤後，修改/etc/mongo.conf，將設定檔中的log和data目錄放在新的資料盤下，並修改檔案的存取權限。改完後的mongo.conf:

# mongod.conf# for documentation of all options, see:#   http://docs.mongodb.org/manual/reference/configuration-options/# where to write logging data.systemLog:  destination: file  logAppend: true  path: /data/mongodb/log/mongod.log# Where and how to store data.storage:  dbPath: /data/mongodb/data.....

檔案許可權：

# ls -alhdrwxr-xr-x.  5 mongod mongod 4.0K 11月  1 14:53 mongodb# cd mongodb# ls -alhdrwxr-xr-x. 3 mongod mongod 4.0K 11月  9 19:08 datadrwxr-xr-x. 2 mongod mongod 4.0K 11月  9 19:06 logdrwxr-xr-x. 2 mongod mongod 4.0K 11月  1 14:54 run

執行systemctl start mongod命令後，查看狀態發現並沒有啟動，查看/var/log/message，發現以下錯誤

Nov  9 06:06:44 [localhost] setroubleshoot: failed to retrieve rpm info for /data/mongodb/run/mongod.pidNov  9 06:06:44 [localhost] setroubleshoot: SELinux is preventing /usr/bin/mongod from write access on the file /data/mongodb/run/mongod.pid. For complete SELinux messages run: sealert -l f7148e11-b126-401e-ba9f-a9a87c1e54aeNov  9 06:06:44 [localhost] python: SELinux is preventing /usr/bin/mongod from write access on the file /data/mongodb/run/mongod.pid.#012#012*****  Plugin restorecon (94.8 confidence) suggests   ************************#012#012If you want to fix the label. #012/data/mongodb/run/mongod.pid default label should be default_t.#012Then you can run restorecon.#012Do#012# /sbin/restorecon -v /data/mongodb/run/mongod.pid#012#012*****  Plugin catchall_labels (5.21 confidence) suggests   *******************#012#012If you want to allow mongod to have write access on the mongod.pid file#012Then you need to change the label on /data/mongodb/run/mongod.pid#012Do#012# semanage fcontext -a -t FILE_TYPE '/data/mongodb/run/mongod.pid'#012where FILE_TYPE is one of the following: afs_cache_t, initrc_tmp_t, mongod_log_t, mongod_tmp_t, mongod_var_lib_t, mongod_var_run_t, puppet_tmp_t, user_cron_spool_t.#012Then execute:#012restorecon -v '/data/mongodb/run/mongod.pid'#012#012#012*****  Plugin catchall (1.44 confidence) suggests   **************************#012#012If you believe that mongod should be allowed write access on the mongod.pid file by default.#012Then you should report this as a bug.#012You can generate a local policy module to allow this access.#012Do#012allow this access for now by executing:#012# ausearch -c 'mongod' --raw | audit2allow -M my-mongod#012# semodule -i my-mongod.pp#012

從提示中可以看出是SELinux的防護功能，阻止了訪問。 解決過程：

/var/log/message中的資訊看起來比較費勁，裡面有一句提示：

For complete SELinux messages run: sealert -l e73ba9e8-f74d-4835-9b53-85667546b28c

根據提示執行：

# sealert -l e73ba9e8-f74d-4835-9b53-85667546b28cSELinux is preventing /usr/bin/mongod from write access on the directory /data/mongodb/log.*****  Plugin catchall_labels (83.8 confidence) suggests   *******************If you want to allow mongod to have write access on the log directoryThen 必須更改 /data/mongodb/log 中的標籤Do# semanage fcontext -a -t FILE_TYPE '/data/mongodb/log'其中 FILE_TYPE 為以下內容之一：mongod_log_t, mongod_tmp_t, mongod_var_lib_t, mongod_var_run_t, tmp_t, var_lib_t, var_log_t, var_run_t。然後執行：restorecon -v '/data/mongodb/log'*****  Plugin catchall (17.1 confidence) suggests   **************************......

上面提示輸出中已經包含了，解決方案：

# semanage fcontext -a -t mongo_log_t '/data/mongodb/log'# restorecon -v '/data/mongodb/log'restorecon reset /data/mongodb/log context unconfined_u:object_r:unlabeled_t:s0->unconfined_u:object_r:mongod_log_t:s0

上面命令執行完畢後，就解決了/data/mongodb/log目錄的檔案許可權問題。

同樣的方法，再解決/data/mongodb/data和/data/mongodb/run目錄的問題。

啟動mongod，問題解決。

Nov  9 06:08:51 [localhost] systemd: Starting High-performance, schema-free document-oriented database...Nov  9 06:08:51 [localhost] systemd: Started High-performance, schema-free document-oriented database.Nov  9 06:08:51 [localhost] mongod: about to fork child process, waiting until server is ready for connections.Nov  9 06:08:51 [localhost] mongod: forked process: 18218Nov  9 06:08:51 [localhost] mongod: child process started successfully, parent exiting

P.S. 除了上面通過提示資訊解決問題外，還有一個比較暴力的方法，直接關閉SELinux，但是不太建議。

# setenforce 0# getenforcePermissive

上面是臨時關閉，如果是永久關閉，就需要編輯/etc/selinux/config檔案，將SELINUX=enforcing改為SELINUX=disabled，但是只有重啟後才會發揮作用。