VirtualTam's bookmarks
21 bookmarks found
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criu: Checkpoint/Restore tool
2022-12-06 Checkpoint/Restore In Userspace, or CRIU (pronounced kree-oo, IPA: /krɪʊ/, Russian: криу), is a Linux software. It can freeze a running container (or an individual application) and checkpoint its state to disk. The data saved can be used to restore the application and run it exactly as it was during the time of the freeze. Using this functionality, application or container live migration, snapshots, remote debugging, and many other things are now possible.
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- https://www.doctrine-project.org/projects/orm.html
- https://www.doctrine-project.org/projects/doctrine-dbal/en/2.7/index.html
- https://www.doctrine-project.org/projects/doctrine-migrations/en/1.7/index.html
- https://github.com/doctrine
- https://symfony.com/doc/current/doctrine.html
- https://symfony.com/doc/current/doctrine/associations.html
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Here are the steps I used to migrate a CentOS 7 VM from (presumably?) an ESXi server, to a local VirtualBox environment.
The LVM volumes were not detected at boot, and after the boot timeout, the OS fell back to the Dracut emergency shell.
- get a CentOS minimal installation CD
- check the VM's resources and peripherals:
- ensure there are no floppy drives (!)
- setup CPU and RAM resources
- check virtual drives
- add an SCSI optical drive if needed
- optional: convert the virtual drive images from VMDK to VDI
- mount the CentOS installation disc
- boot on the installation disc:
- select "Troubleshooting", then "Rescue"
- let the rescue utility detect filesystems and mountpoints
$ chrootto the detected environment- backup files:
/etc/fstab/boot/grub/grub.cfg
- under /boot, backup the initrd and initramfs for the current configuration (these will be overwritten)
- compare the current
/etc/fstabwith the output of$ lsblkand$ blkid - if needed, manually edit /etc/fstab to use the appropriate block device UUIDs, identifiers and mountpoints
- regenerate GRUB configuration:
$ grub2-mkconfig -o /boot/grub2/grub.cfg
- if needed, reinstall GRUB:
$ grub-install /dev/sda
- rebuild initrd:
$ mkinitrd --force /boot/<initrd_image> <kernel_version>
- rebuild initramfs:
$ dracut --force <kernel_version>
- exit the chroot
- unmount the installation disc
- reboot
- optional but highly recommended: cross your fingers
- ...
- profit!
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Migrating to Sensu
2018-04-04 - https://roobert.github.io/2015/11/09/Sensu-What/
- https://blog.sensuapp.org/our-journey-implementing-sensu-to-monitor-kubernetes-in-production-5764aff2dd50
- https://phillbarber.blogspot.fr/2015/03/nagios-vs-sensu-vs-icinga2.html
- https://www.reddit.com/r/devops/comments/56xrnj/how_are_people_suffering_through_sensu_core/
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Migrating a 130TB Cluster from Elasticsearch 2 to 5 in 20 Hours with 0 Downtime and a Rollback…
2018-01-31 - https://thoughts.t37.net/how-we-reindexed-36-billions-documents-in-5-days-within-the-same-elasticsearch-cluster-cd9c054d1db8
- https://thoughts.t37.net/how-we-upgraded-a-22tb-mysql-cluster-from-5-6-to-5-7-in-9-months-cc41b391895d
- https://www.elastic.co/blog/hot-warm-architecture-in-elasticsearch-5-x
- https://www.graylog.org/post/back-to-basics-using-a-hot-warm-elasticsearch-cluster
- https://github.com/mraad/es-hot-warm
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Actors:
- database server / cluster
- load-balanced application servers relying on a database schema with migrations
- reverse proxy
Issue:
- managing database schema migrations
Possible sequence:
- create the database
- run a service that executes database schema migrations
- start application servers
- start the load-balancer / reverse-proxy
Resources:
- https://www.reddit.com/r/docker/comments/2t2pnf/what_are_best_strategies_to_migrate_relational/
- https://softwareengineering.stackexchange.com/questions/357929/db-migration-strategy-for-docker-containers-in-aws-ecs
- https://stackoverflow.com/questions/41592091/run-a-database-migration-command-when-deploying-a-docker-container-to-aws
- https://ltd-keeper.lsst.io/gke-migrations.html
- https://stackoverflow.com/questions/31715239/docker-compose-database-migrations-and-other-pre-post-scripts
- https://stackoverflow.com/questions/38089999/docker-compose-rails-best-practice-to-migrate
- https://stackoverflow.com/questions/37058812/how-best-to-run-one-off-migration-tasks-in-a-kubernetes-cluster
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Django, Docker and MySQL
2017-11-29 Django ORM:
- https://docs.djangoproject.com/en/1.11/ref/databases/#mysql-notes
- https://stackoverflow.com/questions/34777755/how-to-config-django-using-pymysql-as-driver
- https://stackoverflow.com/questions/19189813/setting-django-up-to-use-mysql
MySQL / MariaDB / Percona connectors:
- https://stackoverflow.com/questions/4960048/python-3-and-mysql
- https://github.com/PyMySQL/PyMySQL
- https://pypi.python.org/pypi/mysql-connector-python
Docker images:
- https://store.docker.com/images/mariadb
- https://store.docker.com/images/mysql
- https://store.docker.com/images/percona
Compose and Django ORM database migrations:
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I've inherited 200K lines of spaghetti code -- what now? - Software Engineering Stack Exchange
2017-10-16 - https://softwareengineering.stackexchange.com/questions/6395/how-do-you-dive-into-large-code-bases
- https://softwareengineering.stackexchange.com/questions/6268/when-is-a-big-rewrite-the-answer
- https://www.red-gate.com/blog/software-development/legacy-code
- https://craftedsw.blogspot.ro/2011/06/change-in-attitude-legacy-code.html
- https://www.joelonsoftware.com/2000/04/06/things-you-should-never-do-part-i/
- https://www.reddit.com/r/PHP/comments/7blo1b/refactoring_huge_ci_2_application/
- https://leanpub.com/mlaphp
- https://softwareengineering.stackexchange.com/questions/184227/migrating-legacy-procedural-code-to-mvc-without-rewriting/184241
- https://www.reddit.com/r/PHP/comments/ax88ot/i_am_taking_on_a_custom_crappy_php_application/
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SVN to Git | Atlassian Git Tutorial
2017-03-30 - https://git-scm.com/book/en/v2/Git-and-Other-Systems-Git-as-a-Client
- https://git-scm.com/book/en/v2/Git-and-Other-Systems-Migrating-to-Git
- https://github.com/svn-all-fast-export/svn2git
- https://github.com/ColinFinck/reactos-git-conversion-scripts
- https://svn.reactos.org/project-tools/trunk/git-tools/
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Original script @ https://gist.github.com/yuvipanda/5174162
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Dive Into Python 3
2014-11-30 A follow-up to Mark Pilgrim's http://www.diveintopython.net/