CDH中HDFS的部分Datanode下线

太过爱你忘了你带给我的痛 2021-11-17 23:30 943阅读 0赞

##### 1. 准备工作及调整相关参数 #####

1.  ###### 检查 HDFS 文件系统 ######
    
        hdfs fsck / -list-corruptfileblocks -openforwrite -files -blocks -locations
2.  ###### 修复检查出的问题 ######
    
        hdfs fsck file_name -move
        或
        hdfs fsck file_name -delete
3.  ###### 调整DataNodes的堆大小 ######
    
    HDFS -> 配置 -> DataNode -> 资源管理 -> 搜索 “Java Heap” -> 保存更改
    
    ![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzIxNTI1MA_size_16_color_FFFFFF_t_70][]
    
    DataNodes 堆大小至少配置 4 GB，以允许迭代和最大流的增加。.
4.  ###### 设置DataNode平衡带宽 ######
    
    HDFS -> 配置 -> DataNode -> 性能 -> 搜索 “bandwidth” -> 保存更改
    
    ![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzIxNTI1MA_size_16_color_FFFFFF_t_70 1][]
    
    DataNode 平衡带宽值应小于磁盘和网络上的带宽，以最大限度地减少对群集的影响，但需花费更长时间。
5.  ###### 根据需要更改可用空间策略平衡的阈值 ######
    
    HDFS -> 配置 -> DataNode -> 高级 -> 搜索 “balanced” -> 保存更改
    
    ![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzIxNTI1MA_size_16_color_FFFFFF_t_70 2][]
6.  ###### 调整线程数 ######
    
    HDFS -> 配置 -> DataNode -> 搜索 “threads” -> 保存更改
    
    ![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzIxNTI1MA_size_16_color_FFFFFF_t_70 3][]

###### 2. 配置需下线的 DataNode ######

1.  ###### 配置下线 DataNode 的 hostname 或 IP ######
    
    HDFS -> 配置 -> 搜索 “dfs\_host” -> 保存更改
    
    ![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzIxNTI1MA_size_16_color_FFFFFF_t_70 4][]
2.  ###### 刷新配置 ######
    
        hadoop dfsadmin -refreshNodes
    
    ![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzIxNTI1MA_size_16_color_FFFFFF_t_70 5][]  
    ![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzIxNTI1MA_size_16_color_FFFFFF_t_70 6][]

###### 3. 查看 DataNode 状态，并等待下线完成 ######

打开 NameNode Web UI  
此时可以查看到正在下线的机器  
![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzIxNTI1MA_size_16_color_FFFFFF_t_70 7][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzIxNTI1MA_size_16_color_FFFFFF_t_70 8][]

DataNode 状态变为 Decommissioned 表示下线完成。  
![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzIxNTI1MA_size_16_color_FFFFFF_t_70 9][]

###### 4. 下线DataNode ######

等待需下线的 DataNode 状态变为 Decommissioned，再执行下面操作。

停止 -> 解除授权 -> 删除 -> 重启 HDFS 服务

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzIxNTI1MA_size_16_color_FFFFFF_t_70 10][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzIxNTI1MA_size_16_color_FFFFFF_t_70 11][]

###### 5. 清空 dfs\_hosts\_exclude.txt配置并刷新群集 ######

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzIxNTI1MA_size_16_color_FFFFFF_t_70 12][]  
![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzIxNTI1MA_size_16_color_FFFFFF_t_70 13][]

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