mimastech.com

MongoDB 4.0 Community Edition can be installed on RPM-based Linux systems (Red Hat Enterprise Linux 7, CentOS 7, Scientific Linux 7, and recent Fedora releases) by adding the official MongoDB 4.0 repository, then installing the mongodb-org package with yum. This guide covers the repository setup, the install command, starting and enabling the service, and how to confirm the installation worked. It applies to 64-bit RPM-family systems; if you are on a non-RPM distribution such as Debian or Ubuntu, the package manager and repository steps differ.

Prerequisites

Before you start, confirm the following:

• A 64-bit CentOS 7, RHEL 7, Scientific Linux 7, or a recent Fedora release.
• Root or sudo access, since repository files and service management require elevated privileges.
• A working network connection to reach the MongoDB repository.
• SELinux and firewall settings you can adjust if you plan to accept remote connections (the default install listens locally).

Step 1: Add the MongoDB 4.0 Repository

MongoDB is not in the default CentOS/RHEL repositories, so you add a repo file that points to the official 4.0 packages. Create the repository definition:

sudo vi /etc/yum.repos.d/mongodb-org-4.0.repo

Add the following content:

[mongodb-org-4.0]
name=MongoDB Repository
baseurl=https://repo.mongodb.org/yum/redhat/$releasever/mongodb-org/4.0/x86_64/
gpgcheck=1
enabled=1
gpgkey=https://www.mongodb.org/static/pgp/server-4.0.asc

Save and exit. The baseurl uses $releasever, which yum resolves to your system's major version, so the same file works across the supported RPM releases. gpgcheck=1 with the MongoDB GPG key means packages are verified before installation.

Step 2: Install the MongoDB Packages

Install the mongodb-org metapackage, which pulls in the server, shell, and related tools:

sudo yum install -y mongodb-org

Expected result: yum downloads the packages from the repository you added and installs them. When it finishes, the MongoDB server binaries, the mongo shell, and the default configuration file (/etc/mongod.conf) are in place.

If you want to prevent yum from automatically upgrading MongoDB to a newer minor version later, you can pin the version by editing /etc/yum.conf and adding an exclude line for the MongoDB packages. This is optional and only matters if you need strict version control.

Step 3: Start and Enable the MongoDB Service

Start the service and set it to start on boot:

sudo systemctl start mongod
sudo systemctl enable mongod

Expected result: systemctl start returns without error, and enable creates the symlink so MongoDB starts automatically after a reboot.

Check the service status:

sudo systemctl status mongod

You should see an active (running) state. If the service fails to start, the most common causes are a permissions problem on the data directory (/var/lib/mongo) or a configuration error in /etc/mongod.conf.

Step 4: Verify the Installation

Confirm the server is reachable and check its version by opening the MongoDB shell:

mongo --eval 'db.runCommand({ connectionStatus: 1 })'

A successful connection returns a document showing ok: 1 and the authenticated/available users. To check the exact server version:

mongod --version

The output should report MongoDB 4.0.x, confirming the 4.0 Community Edition is installed.

Common Issues and Fixes

What MimasTech Covers

MimasTech is a Linux technical blog and services site that publishes tutorials on Linux OS, virtualization, databases, and security. Its MongoDB 4.0 installation article is part of a series that also covers installing PHP 7.x versions on CentOS 7/RHEL 7, using the awk command for text processing, installing Docker on Debian 9, and installing Google Chrome on Ubuntu 18.04. The site also invites readers to submit their own experience for publication. If you are working through RPM-based server setup, its PHP and MongoDB guides are the most directly relevant.

Next Steps

After MongoDB is running, the usual follow-up tasks are creating an admin user, enabling authentication in /etc/mongod.conf, and configuring backups. The install itself is complete once mongod --version reports 4.0.x and the service is active.

If you're new to Ahrefs and want to run your first SEO audit, the fastest path is: open Site Explorer, enter your target URL, review the Overview for a health snapshot, then dig into Organic Keywords, Top Pages, and Site Audit to find specific problems. From there, build a short prioritized to-do list instead of trying to fix everything at once.

This tutorial walks through that workflow using a realistic starting scenario, explains what the numbers mean, and shows how to turn findings into actions.

Before You Start: Pick a Narrow Scope

A common beginner mistake is auditing an entire large website on day one. The reports become overwhelming, and you can't tell which issues matter.

Instead, choose one of these starting points:

• A single important page (your homepage or a key product/service page)
• A small site (under ~50 pages, e.g., a personal blog or small business site)
• One section of a bigger site (e.g., /blog/)

For this tutorial, assume you're auditing a small business site with about 30 pages. The same steps scale up later.

You'll need an Ahrefs account to follow along. Ahrefs offers paid plans, and pricing and feature limits change over time, so check the current Pricing page for what's included in each tier before committing.

Step 1: Enter Your Target in Site Explorer

Site Explorer is Ahrefs' core tool for analyzing any website or URL.

1. Open Site Explorer from the top navigation.
2. In the search box, paste your domain (e.g., example.com).
3. Choose the Exact URL or Domain mode depending on scope. For a full-site view, use Domain or Prefix; for a single page, use Exact URL.
4. Press Enter.

You'll land on the Overview report. Don't try to absorb everything — focus on four numbers first.

Reading the Overview Snapshot

Important caveat: Ahrefs' traffic and keyword numbers are estimates based on its own data. They won't match Google Search Console or your analytics exactly. Treat them as directional, not absolute.

Step 2: See What You Already Rank For

Go to Organic Keywords in the left sidebar. This shows queries where your site appears in search results.

Sort by Traffic (descending) to see which pages bring the most estimated visitors. Then look for:

• Keywords ranking in positions 4–15 — these are often the easiest wins. A small content or on-page improvement can push them onto page one.
• Keywords with high volume but low position — potential opportunities if the topic is relevant.
• Irrelevant keywords — if you rank for something off-topic, it may signal thin or mismatched content.

Write down 5–10 of the position 4–15 keywords. These become your first optimization targets.

Step 3: Find Your Best and Weakest Pages

Open Top Pages. This ranks your URLs by estimated organic traffic.

Look for two things:

1. Your top performers — understand what topics and formats work. Can you create more content like this?
2. Pages with traffic but poor rankings — these may need on-page fixes (title, headings, internal links).

If a page gets zero traffic and targets a topic you care about, it's a candidate for a rewrite or consolidation.

Step 4: Run a Technical Site Audit

Now move to Site Audit. This crawls your site and flags technical and on-page issues.

1. Click Site Audit → New project.
2. Enter your domain and set crawl settings (default is usually fine for a small site).
3. Start the crawl and wait for it to finish.

Once complete, you'll see a Health Score and a list of issues grouped by category.

Which Issues to Fix First

Not all issues are equal. Prioritize in this order:

Ignore low-impact warnings (like minor meta description length) until the big items are handled.

Step 5: Turn Findings Into a To-Do List

You now have raw data. Convert it into a short, actionable list. Example:

1. Fix 3 broken links found in Site Audit.
2. Rewrite title tags on 5 pages with duplicate titles.
3. Improve 4 pages ranking in positions 6–12 by adding missing subtopics and internal links.
4. Remove or update 2 thin pages with no traffic.

Keep the list to 5–10 items max for your first audit. Finishing a short list beats starting a long one.

Common Beginner Mistakes

• Chasing every red flag. Site Audit flags many minor issues. Fix what affects rankings and users first.
• Trusting estimates as exact numbers. Ahrefs data is modeled, not measured from your analytics.
• Auditing a huge site too early. Start small to learn the interface.
• Ignoring search intent. A page can be technically perfect but still fail if it doesn't match what searchers want.
• Forgetting to re-crawl. After fixes, run Site Audit again to confirm improvements.

Where to Go Next

Once your first audit is done:

• Compare with competitors using Site Explorer's Competing Domains and Content Gap reports.
• Track keyword rankings over time with Rank Tracker.
• Explore backlink opportunities in the Backlinks and Link Intersect reports.
• Set up recurring Site Audit crawls so new issues surface automatically.

Your first audit isn't about perfection — it's about building a repeatable habit: enter a target, read the key reports, pick the highest-impact fixes, and act. Do that once a month and your site's health compounds.

MimasTech is a Linux-focused technical blog and services site that publishes step-by-step tutorials, tips, and full solutions for system administrators and developers. It is most useful if you work with RPM-family Linux distributions (Red Hat, CentOS, Scientific Linux, Fedora) or Debian/Ubuntu systems and want practical, command-level walkthroughs rather than high-level overviews.

What MimasTech covers

The site organizes its content into a small set of recurring categories, visible in its main navigation:

• Linux OS — installation and configuration guides for common distributions
• Virtualization — virtual machine and disk management tasks
• Databases — database engine installation and troubleshooting
• Security — hardening and security-related configuration
• Services & Tools — server software and utilities
• FAQs — short answers to recurring problems

The kind of content you'll find

MimasTech's published posts are hands-on tutorials. Representative examples from its latest posts list include:

Two patterns stand out. First, the tutorials target specific version pairs — for example, PHP 7.3 on CentOS 7 — rather than generic "install PHP" instructions, which matters because the repository setup differs between versions. Second, the site mixes installation guides with debugging notes, such as the PostgreSQL/Rails encoding error, so it functions as a reference for problems as well as a starting point for new setups.

Who it's for

MimasTech is aimed at people who already have shell access and want to follow along. The tutorials assume a bare or near-bare system and walk through repository configuration, package installation, and service startup. If you are looking for conceptual explanations of how MongoDB or Docker works internally, this is not the primary focus; if you need the exact commands to get a specific version running on a specific distribution, it is.

Community contribution

The site explicitly invites readers to submit their own experience for publication, framing the blog as a shared knowledge base: "Share us building the greatest blog ever by sending us your experience to share it with others." That means content quality and depth can vary between posts, and newer submissions may cover setups the core tutorials don't.

Services and payment

MimasTech lists a "Services & Tools" section alongside its blog content, indicating it offers services in addition to written tutorials. PayPal appears as a payment platform on the site. Specific service offerings, scope, and pricing are not detailed in the available site information, so check the Services & Tools page directly if you need those details.

How to get the most out of it

• Match your distribution and version first. Because posts are version-specific, confirm the tutorial targets your exact OS release before following it.
• Read the full post before running commands. Installation guides often include repository changes that affect other packages on the system.
• Use the troubleshooting posts as references. Error-message-based articles, like the Rails encoding fix, are useful when you hit the same message rather than as general reading.
• Check the date. Version-specific guides age quickly once upstream repositories move on.