Ahmed Aboulnaga - Chronicles of Technology

Why does Linux report 100% memory usage all the time?

Why does Linux report memory usage as being 99% used even though nothing is running on the server? I'll start with the conclusion: If little swap is being used, then

Keycloak

Install and Startup Keycloak

Keycloak is an open source software product (Apache License 2.0) identity and access management solution. This post walks you through an extremely quick setup of this product. Download KeycloakDownload

SSH

Login to Linux using SSH Keys in PuTTY

This post provides a quick guide to configuring access to a Linux account using SSH keys. Generate a Private and Public Key PairDownload puttygen.exe from here.Click Generate.Move

Linux

Getting "Argument list too long" when using ls

I was trying to count the number of files in a particular directory in Linux using the ls command and received the following error: oracle@soadev:/home/oracle> ls /u01/archive/*.* | wc -l -bash: /bin/ls: Argument list too longTurns out the resolution

Linux

Find directories with largest number of files in Linux

I needed to find the list of directories that had the largest number of files on my Linux file system, searching recursively through the filesystem. Here's the content you can paste in a script: #!/bin/bash if [ $# -ne 1 ];then echo "Usage: `basename $0`

OPatch

Getting OPatch error code 255 and 1

I ran OPatch against my Oracle Access Manager (OAM) 12.2.1.4 installation, and I got the OPatch error code 255. oracle@soadev:/u01/oracle/middleware/OPatch> ./opatch lsinventory OPatch failed with error code 255I guess I had to set the ORACLE_

GCP

Absolutely insane billing from Google Cloud Platform!

Google Cloud Platform (aka GCP) has the most insane approach to charging that I've ever seen. I haven't experienced this with any other cloud service provider such as Amazon Web

Oracle Cloud

Is Oracle Cloud really that cheap?

In January 2019, I conducted performance tests of various compute cloud providers, specifically against services from Amazon Web Services (AWS), Oracle Cloud Infrastructure (OCI), IBM Cloud, Google Cloud Platform (GCP)

WebLogic

OutOfMemoryError when running bsu.sh

I was trying to apply a CPU (Critical Patch Update) on an older version of Oracle WebLogic Server, namely 11g (10.3.6). This is done through the bsu utility. I received the following OutOfMemory exception when trying to apply the patch: oracle@weblogicdev:

Networking

TTL expired in transit on Windows client

Normally I get speeds in excess of 100 Mbps on my home wifi on both uploads and downloads. Speeds during normal operationThis morning, it was down to 6-10 Mbps and I couldn't figure out why. I tried connecting to my router's gateway at 192.

JDeveloper

Running into IntegratedWebLogicServer issues for Windows users with spaces

When attempting to start the IntegratedWebLogicServer in Oracle JDeveloper 12.2.1.3, I received the following error: Error: Could not find or load main class Aboulnaga\AppData\Roaming\JDeveloper\system12.2.1.3.42.170820.0914\DefaultDomainAnd here's a screenshot from the IDE:

JDeveloper

Can't create OSB Business Service in JDeveloper 12.2.1.3

I ran into an error recently where I wasn't able to create a Business Service when developing an Oracle Service Bus (OSB) project in Oracle JDeveloper 12.2.1.3.

Ghost

ER_MUST_CHANGE_PASSWORD_LOGIN on Ghost blog platform

Seems that our Ghost blog platform received the following error when I tried to publish a post: Internal server error, cannot list posts. ER_MUST_CHANGE_PASSWORD_LOGIN: Your password

Don't kid yourself - you're not a Cloud Architect

With the boom in cloud adoption, many IT professionals are looking to formalize their new skillsets by acquiring various cloud certifications. Last week, I took advantage of Oracle's free training

Certification

What you need to pass the OCI Architect Associate certification exam

In March 2020, Oracle announced free access to online learning content and certifications to a broad array of Oracle Cloud certifications for about 2 months (details here). Literally tens of

Compute Cloud

Setting up our compute cloud virtual machines for POCs

We've been doing some quick performance testing of Oracle software on various compute cloud providers that include AWS, Oracle Cloud, IBM Cloud, Google Cloud, and Microsoft Azure. Once the virtual machine is created, most setup/configuration is generally standard. This post is mostly self-documentation

JDBC

Using "utils.dbping" to test JDBC database connectivity

Recently I ran into a problem with an Oracle WebLogic Server data source. We were getting an IO Error: Connection reset in the console and logs when we try to

OCI

Can't find the "oci" executable in Oracle Cloud?

A few months ago, I attended an Oracle Cloud Infrastructure workshop in Oracle Reston. In one of the hands-on labs, it appears that the oci executable was not found in

OEM

Yet another custom OEM uptime report

Here is my custom availability report in Oracle Enterprise Manager (OEM) 13c (using Information Publisher). It consists of multiple elements across multiple rows. Though this report is specific to WebLogic Managed Servers, it could apply to any target type. Each element is a distinct

OEM

Create a custom OEM uptime report for business hours only

There was a need to create a custom Information Publisher Report in Oracle Enterprise Manager 13c to provide uptime metrics. These uptime metrics were to be calculated weekly, from Monday to Friday, only for the hours of 8am to 5pm, and for specific targets.

OEM

Create a custom metric extension in OEM 13c

Oracle Enterprise Manager (OEM) 13c is a solid and comprehensive monitoring tool, providing a long list of monitoring metrics across a large number of target types. But there are bound

Script

Ugly (but quick) script to get Oracle Fusion Middleware software versions

I created a quick script that I ran across all our environments to consolidate a list of all software versions. This includes versions of: operating system, WebLogic, Java, RDA, OPatch, and OPatch patches. It's a crude script, but quite quick and efficient. It may

OEM

Querying incidents in OEM 13c

Unfortunately, the Incident Manager page in Oracle Enterprise Manager 13c is slow, cumbersome, and lacks customization. Running an SQL query against the OMS repository is extremely quick and efficient and you can get exactly what you need. Here is a simple query to pull

OHS

Web server returning 'Cross-Origin Request Blocked' to browser

With a typical web service call made, the browser debugger is showing a Cross-Origin Request Blocked error because it Did not find method in CORS header, specifically Access-Control-Allow-Methods. The resolution to this is quite simple with Oracle HTTP Server (OHS) 12c. Browser Error: "Did

Bash

How to show a timestamp in Bash history

By default, when you run the history command, it lists the history of all commands previously executed, but it does not include a timestamp. Adding a timestamp to the bash history can easily be accomplished with the HISTTIMEFORMAT Bash variable as shown. export HISTTIMEFORMAT=