P.Haul: live migration using CRIU - Pavel Emelyanov Linux Plumbers 2015, Checkpoint and Restore In Userspace Notes - https://etherpad.openstack.org/p/LPC2015_Checkpoint_Restore

1. P.Haul: live migration using CRIUP.Haul: live migration using CRIU
Pavel Emelyanov
Containers MC, Linux Plumbers, Seattle, 2015

2. Not-so-live migration using CRIUNot-so-live migration using CRIU
• src_host# criu dump -t 123 -D images/
• src_host# scp -r images/ user@dst_host:images/
• dst_host# criu restore -D images/ -d
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3. Almost live migration using CRIUAlmost live migration using CRIU
• dst_host# criu page-server -D images/
• src_host# criu pre-dump -t 123 -D images/pre/
--page-server --address dst_host --port port
--track-mem
• src_host# criu dump -t 123 -D images/dump/ --prev-images ../pre/
• src_host# scp -r images/dump/ user@dst_host:images/
• dst_host# criu restore -D images/ -d
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4. Live migration using CRIULive migration using CRIU
• Perform nodes compatibility checks
– CPUs
– Kernel modules
– Available resources
• Do pre-dumps in a loop
– Or post-copy memory transfer (userfaultfd)
• Copy FS if not shared
• Don't forget container config
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5. Live migration using P.HaulLive migration using P.Haul
• dst_host# p.haul-service --port 123
• src_host# p.haul ovz 100 dst_host:123
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6. Where P.Haul currently isWhere P.Haul currently is
• Written in python
• Lives at github.com/xemul/p.haul
• Knows how to live-migration OpenVZ container
• Calls rsync for chroot()-ed container on local FS
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7. Future of P.Haul?Future of P.Haul?
• Migrate LXC & Docker containers
• Smarter iterations
– Better estimate of memory xfer
– Synchronize memory and disk/FS xfer
• Shared disk/FS auto-detection
• Post-copy live migration
• Send images over the wire (CRIU)
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8. Thank youThank you