elastic snapshot on shared folder problem if using sshfs

if you want to set path.repo on mounted dir for elasticsearch snapshot. You probably will get this permission error, even though the dir seems writable by all user.

java.lang.IllegalStateException: Unable to access 'path.repo' (/mnt/remote_snapshot_on_st02/snap_dir) at org.elasticsearch.bootstrap.FilePermissionUtils.addDirectoryPath(FilePermissionUtils.java:66) ~[elasticsearch-8.8.1.jar:?]

This happen because elasticsearh process is own by user elasticsearch. You need to mount the dir using elasticsearch acc. sudo su -u elasticsearch sshfs myacc@10.10.10.10:/data/my_elastic_snapshot_dir/ /mnt/my_snapshot_dir Of course you need to have set path.repo on your elasticsearch.yml path.repo: [/mnt/my_snapshot_dir/the_snapshot_dir_on_remote]

carian string dlm wireshark

1)

2)

 ref: https://www.cellstream.com/reference-reading/tipsandtricks/431-finding-text-strings-in-wireshark-captures

Sejarah ip yg pernah pc ubuntu anda pegang

 history of ip has been assign to your pc

Ada 2 command yg boleh senaraikan IP yg pc anda dapat dari DHCP.

1) sudo cat /var/log/syslog | grep -Ei 'dhcp' | grep ip_address

2) sudo journalctl | grep -Ei 'dhcp' | grep ip_address

cara install apt package specific version

$ apt-cache madison calc calc | 2.12.7.2-4 | http://10.108.201.140/ubuntu/mirror/archive.ubuntu.com/ubuntu focal/universe amd64 Packages calc | 2.10.18-dfsg-2build1 | http://archive.ubuntu.com/ubuntu xenial/multiverse amd64 Packages

$ apt-cache policy virtualbox virtualbox: Installed: (none) Candidate: 5.0.40-dfsg-0ubuntu1.16.04.2 Version table: 5.0.40-dfsg-0ubuntu1.16.04.2 500 500 http://cm.archive.ubuntu.com/ubuntu xenial-updates/multiverse amd64 Packages 5.0.18-dfsg-2build1 500 

500 http://cm.archive.ubuntu.com/ubuntu xenial/multiverse amd64 Packages 

ref:
https://linuxopsys.com/topics/install-specific-version-package-apt

Cara nak tahu package apa yg ada dalam apt repo tertentu

cd /var/lib/apt/lists

ls

cari file yg berakhir dengan Packages, cth:
    dl.google.com_linux_chrome_deb_dists_stable_main_binary-amd64_Packages

Dalam file ini, tersenarai nama package yg terdapat dalam repo tersebut.

ref:
https://tecadmin.net/list-all-packages-available-in-a-repository-on-ubuntu/

ceph troubleshoot

1) start with

ceph health detail

2) OSD_FULL

Ceph prevent writing to a full OSD. By default 'full' is set to 0.95. Temporary solution, set full to 0.97

    ceph osd set-full-ratio 0.96

ps: to get more info 
1- ceph osd dump | grep full_ratio
2- ceph df

(ref https://docs.ceph.com/en/quincy/rados/operations/health-checks/)

3) POOL_TOO_FEW_PGS

list pools

ceph osd lspools

To allow the cluster to automatically adjust the number of PGs

ceph osd pool set <pool-name> pg_autoscale_mode on

To manually set the number of PGs for the pool to the recommended amount with:

ceph osd pool set <pool-name> pg_num <new-pg-num>

4) BLUESTORE_NO_PER_POOL_OMAP
Stop the osd, repair, then start again:
eg: osd.123

systemctl stop ceph-osd@123
ceph-bluestore-tool repair --path /var/lib/ceph/osd/ceph-123
systemctl start ceph-osd@123

ceph info gathering

 ceph health

ceph heatlh detail