[英]How to attach a Cloud Block Storage volume to an OnMetal server with pyrax?
将Cloud Block Storage卷附加到OnMetal服务器比将其附加到普通Rackspace虚拟服务器要复杂一些。 您会注意到,当您尝试在Rackspace Web界面Cloud Control Panel中将Cloud Block Storage卷附加到OnMetal服务器时,您会看到以下文本:
注意:将卷附加到OnMetal服务器时,必须登录OnMetal服务器以设置启动器名称,发现目标,然后连接到目标。
因此,您可以在Web界面中附加卷,但此外,您还需要登录OnMetal服务器并运行一些命令。 可以将实际命令从Web界面复制并粘贴到OnMetal服务器的终端中。
同样在分离之前,您需要运行命令。
但是实际上不需要Web界面。 可以使用Python模块pyrax来完成。
首先在OnMetal服务器上安装RPM软件包iscsi-initiator-utils
[root@server-01 ~]# yum -y install iscsi-initiator-utils
假设volume_id和server_id已知,则此Python代码首先附加卷,然后分离卷。 不幸的是,mount_point参数attach_to_instance()在OnMetal服务器上不起作用,因此在附加卷之前和之后,我们将需要使用命令lsblk -n -d
。 通过比较输出,我们可以推断出用于连接卷的设备名称。 (下面的Python代码未考虑推断设备名称的部分)。
#/usr/bin/python
# Disclaimer: Use the script at your own Risk!
import json
import os
import paramiko
import pyrax
# Replace server_id and volume_id
# to your settings
server_id = "cbdcb7e3-5231-40ad-bba6-45aaeabf0a8d"
volume_id = "35abb4ba-caee-4cae-ada3-a16f6fa2ab50"
# Just to demonstrate that the mount_point argument for
# attach_to_instance() is not working for OnMetal servers
disk_device = "/dev/xvdd"
def run_ssh_commands(ssh_client, remote_commands):
for remote_command in remote_commands:
stdin, stdout, stderr = ssh_client.exec_command(remote_command)
print("")
print("command: " + remote_command)
for line in stdout.read().splitlines():
print(" stdout: " + line)
exit_status = stdout.channel.recv_exit_status()
if exit_status != 0:
raise RuntimeError("The command :\n{}\n"
"exited with exit status: {}\n"
"stderr: {}".format(remote_command,
exit_status,
stderr.read()))
pyrax.set_setting("identity_type", "rackspace")
pyrax.set_default_region('IAD')
creds_file = os.path.expanduser("~/.rackspace_cloud_credentials")
pyrax.set_credential_file(creds_file)
server = pyrax.cloudservers.servers.get(server_id)
vol = pyrax.cloud_blockstorage.find(id = volume_id)
vol.attach_to_instance(server, mountpoint=disk_device)
pyrax.utils.wait_until(vol, "status", "in-use", interval=3, attempts=0,
verbose=True)
ssh_client = paramiko.SSHClient()
ssh_client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
ssh_client.connect(server.accessIPv4, username='root', allow_agent=True)
# The new metadata is only available if we get() the server once more
server = pyrax.cloudservers.servers.get(server_id)
metadata = server.metadata["volumes_" + volume_id]
parsed_json = json.loads(metadata)
target_iqn = parsed_json["target_iqn"]
target_portal = parsed_json["target_portal"]
initiator_name = parsed_json["initiator_name"]
run_ssh_commands(ssh_client, [
"lsblk -n -d",
"echo InitiatorName={} > /etc/iscsi/initiatorname.iscsi".format(initiator_name),
"iscsiadm -m discovery --type sendtargets --portal {}".format(target_portal),
"iscsiadm -m node --targetname={} --portal {} --login".format(target_iqn, target_portal),
"lsblk -n -d",
"iscsiadm -m node --targetname={} --portal {} --logout".format(target_iqn, target_portal),
"lsblk -n -d"
])
vol.detach()
pyrax.utils.wait_until(vol, "status", "available", interval=3, attempts=0,
verbose=True)
运行python代码如下所示
user@ubuntu:~$ python attach.py 2> /dev/null
Current value of status: attaching (elapsed: 1.0 seconds)
Current value of status: in-use (elapsed: 4.9 seconds)
command: lsblk -n -d
stdout: sda 8:0 0 29.8G 0 disk
command: echo InitiatorName=iqn.2008-10.org.openstack:a24b6f80-cf02-48fc-9a25-ccc3ed3fb918 > /etc/iscsi/initiatorname.iscsi
command: iscsiadm -m discovery --type sendtargets --portal 10.190.142.116:3260
stdout: 10.190.142.116:3260,1 iqn.2010-11.com.rackspace:35abb4bb-caee-4c5e-ad53-a16f6f12ab50
stdout: 10.69.193.1:3260,1 iqn.2010-11.com.rackspace:35abb4bb-caee-4c5e-ad53-a16f6f12ab50
command: iscsiadm -m node --targetname=iqn.2010-11.com.rackspace:35abb4bb-caee-4c5e-ad53-a16f6f12ab50 --portal 10.190.142.116:3260 --login
stdout: Logging in to [iface: default, target: iqn.2010-11.com.rackspace:35abb4bb-caee-4c5e-ad53-a16f6f12ab50, portal: 10.190.142.116,3260] (multiple)
stdout: Login to [iface: default, target: iqn.2010-11.com.rackspace:35abb4bb-caee-4c5e-ad53-a16f6f12ab50, portal: 10.190.142.116,3260] successful.
command: lsblk -n -d
stdout: sda 8:0 0 29.8G 0 disk
stdout: sdb 8:16 0 50G 0 disk
command: iscsiadm -m node --targetname=iqn.2010-11.com.rackspace:35abb4bb-caee-4c5e-ad53-a16f6f12ab50 --portal 10.190.142.116:3260 --logout
stdout: Logging out of session [sid: 5, target: iqn.2010-11.com.rackspace:35abb4bb-caee-4c5e-ad53-a16f6f12ab50, portal: 10.190.142.116,3260]
stdout: Logout of [sid: 5, target: iqn.2010-11.com.rackspace:35abb4bb-caee-4c5e-ad53-a16f6f12ab50, portal: 10.190.142.116,3260] successful.
command: lsblk -n -d
stdout: sda 8:0 0 29.8G 0 disk
Current value of status: detaching (elapsed: 0.8 seconds)
Current value of status: available (elapsed: 4.7 seconds)
user@ubuntu:~$
请注意:
尽管在Rackspace官方文档中未提及
https://support.rackspace.com/how-to/attach-a-cloud-block-storage-volume-to-an-onmetal-server/
在2015年8月5日的论坛帖子中 ,Rackspace托管基础架构支持还建议运行
iscsiadm -m node -T $TARGET_IQN -p $TARGET_PORTAL --op update -n node.startup -v automatic
使连接持久,以便在启动时自动重新启动iscsi会话。
更新资料
关于推断新设备名称:Hayden少校在博客中写道:
[root@server-01 ~]# ls /dev/disk/by-path/
可以用来查找新设备的路径。 如果您想尊重任何符号链接,我想这会起作用
[root@server-01 ~]# find -L /dev/disk/by-path -maxdepth 1 -mindepth 1 -exec realpath {} \;
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