I've been using rundeck (an automation platform) to manage Linux servers for quite a while. Recently I've expanded the practice to Windows servers and have had some difficulties with authentication because either OS packages or Python modules were missing. Rundeck supports 4 types of authentication -- basic, credssp, ntlm, kerberos for the Windows system. It … Continue reading Managing Windows servers with Rundeck?
When working with sudo, one subtle thing is about shell wildcard matching. I didn't notice this until recently I needed to use a script to copy files from a remote server with one user A, but eventually put the files under another user B with changing owernship and permissions. My steps were scp, mv, chown, … Continue reading sudo not working with wildcard matching?
In another post I wrote before, slow SSH login issue -- after you enter the username, it takes some time (a minute or a few) to show the password prompt, could be due to the wrong DNS configuration. And there is a configuration option UseDNS for sshd and by default it's enabled (value yes) which … Continue reading Troubleshooting SSH slow login
If you have been working on Linux for some time -- longer than a few years, you probably has come from runlevel days which the services are managed by SysV init scripts. So you are familiar with the commands like shutdown, init, halt, reboot etc. which are used to start, stop or bring the system … Continue reading reboot, shutdown, halt & systemctl
In another post I wrote some time ago, I ran into the error ORA-20001 during the datapatch of a 19c upgrade. I got the same error but with a different reason this time: temp data files missing due to OS changes. So we moved a 12c datatabase from Oracle Linux 6 to Oracle Linux 8 … Continue reading Another reason for verify_queryable_inventory returned ORA-20001: Latest xml inventory is not loaded into table
BASH is one of popular shell environment on Linux OS. And when using it, everyone loves the auto complete feature, you just tab after you enter first few letters and BASH will match commands/files for you. However, a few weeks ago when I went into a newly staged Oracle Linux 8 system with some kind … Continue reading BASH auto complete doesn’t work? Watch out the mount option “noexec”
This was the exactly the same problem I ran into before on auditd. The log directory for sssd was recreated somehow but the context of SELinux was not restored. That caused even root could not create the sssd logs under the directory and the service could not start. sssd[sssd]: Could not open file [/var/log/sssd/sssd.log]. Error: … Continue reading Could not open file /var/log/sssd/sssd.log –Permission denied
When patching a 19c database, I ran into an issue when it's trying to roll back the old OJVM patch and applying the newer one. UtilSession failed: RollbackSession failed in system modification phase... 'Archive not rolled back /opt/oracle/190000/.patch_storage/33561310_Jan_5_2022_08_13_10/files/lib/libserver19.a/joxwtp.o to /opt/oracle/190000/lib/libserver19.a... ' OPatch failed with error code 73 It's strange because I could see the backup … Continue reading RollbackSession failed in system modification phase — Archive not rolled back
After installing Ubuntu on an old Dell laptop to replace Windows 7, I've noticed the WiFi LED indicator kept blinking all the time which is quite annoying. That reminded me a couple year ago when I switched on winter tires for the first time on my car, the tire pressure warning light turned on because … Continue reading Ubuntu — Stop constantly blinking WiFi LED
By default, AWS CLI or PowerShell AWS cmdlets only list EC2 resources from your default region. You need to specify a region to see what services are there or a profile created with AWS CLI's configuration which contains a different region. Within the AWS Management Console, you can use "EC2 Global View" to list all … Continue reading PowerShell getting AWS instances from all regions