构建Kraken2数据库遇域名解析错误，请求技术支持

问题重现 #

执行Kraken2数据库构建命令时：

kraken2-build --download-library archaea --db archaea_DB
kraken2-build --download-library viral --db viral_DB
kraken2-build --download-library bacteria --db bacteria_DB
kraken2-build --download-library human --db human_DB
kraken2-build --download-library fungi --db fungi_DB
kraken2-build --download-library protozoa --db protozoa_DB

出现统一错误：无法解析ftp.ncbi.nlm.nih.gov地址，具体错误输出如下：

rsync: getaddrinfo: ftp.ncbi.nlm.nih.gov 873: Temporary failure in name resolution

rsync error: error in socket IO (code 10) at clientserver.c(138) [Receiver=3.2.6]

Error downloading assembly summary file for archaea, exiting.
rsync: getaddrinfo: ftp.ncbi.nlm.nih.gov 873: Temporary failure in name resolution

rsync error: error in socket IO (code 10) at clientserver.c(138) [Receiver=3.2.6]
Error downloading assembly summary file for viral, exiting.
rsync: getaddrinfo: ftp.ncbi.nlm.nih.gov 873: Temporary failure in name resolution
rsync error: error in socket IO (code 10) at clientserver.c(138) [Receiver=3.2.6]

Error downloading assembly summary file for bacteria, exiting.
rsync: getaddrinfo: ftp.ncbi.nlm.nih.gov 873: Temporary failure in name resolution
rsync error: error in socket IO (code 10) at clientserver.c(138) [Receiver=3.2.6]
Error downloading assembly summary file for human, exiting.
rsync: getaddrinfo: ftp.ncbi.nlm.nih.gov 873: Temporary failure in name resolution

rsync error: error in socket IO (code 10) at clientserver.c(138) [Receiver=3.2.6]
Error downloading assembly summary file for fungi, exiting.
rsync: getaddrinfo: ftp.ncbi.nlm.nih.gov 873: Temporary failure in name resolution
rsync error: error in socket IO (code 10) at clientserver.c(138) [Receiver=3.2.6]
Error downloading assembly summary file for protozoa, exiting.

解决方案 #

1. 排查本地DNS配置 #

• 先手动验证域名解析能力：

  nslookup ftp.ncbi.nlm.nih.gov
  

  若无解析结果，说明本地DNS无法识别该域名，可更换公共DNS：
  • 临时生效：编辑/etc/resolv.conf，添加nameserver 8.8.8.8
  • 永久生效：根据Linux发行版调整网络配置文件（如/etc/netplan或/etc/sysconfig/network-scripts）

2. 用IP地址替代域名访问 #

• 先获取NCBI FTP服务器的有效IP：

  dig ftp.ncbi.nlm.nih.gov +short
  

• 执行下载命令时指定IP：

  kraken2-build --download-library archaea --db archaea_DB --rsync-server <获取到的IP>::genomes/
  

3. 检查网络与代理设置 #

• 验证外网连通性：ping google.com
• 若处于代理环境，设置rsync代理变量：

  export RSYNC_PROXY="http://你的代理IP:端口"
  

4. 手动下载构建数据库 #

若以上方法无效，可直接从NCBI FTP站点下载对应物种的组装文件和基因组数据，通过以下步骤手动构建：

1. 将下载的文件添加到数据库：kraken2-build --add-to-library <文件路径> --db your_db_name
2. 完成数据库构建：kraken2-build --build --db your_db_name

内容的提问来源于stack exchange，提问作者Zavaliño