In enterprise air-gapped environments or DMZ zones where direct connection to external networks is restricted due to security constraints, installation errors caused by missing dependent libraries are a frequent challenge when deploying the HAProxy load balancer anew. RHEL 8 adopts DNF (Dandified YUM) as its standard package management system, strongly requiring an operational design where all dependencies (Dependency Graph) are resolved and packages are acquired in advance in an online environment, and then configured as a local repository on the target verification machine.

Extracting Packages and All Dependencies in an Online Environment

To prepare the package set to be brought into the air-gapped network, first extract HAProxy and the shared libraries required for its runtime (openssl-libs, pcre2, systemd, etc.) on a workstation node with internet connectivity.

Rather than acquiring only the main RPM, execute with a combination of the --resolve and --alldeps options to collect all libraries not yet installed in the target environment without omission.

sudo dnf download --resolve --alldeps --destdir=/tmp/haproxy_rpms haproxy

Parameter Configuration Specifications

• --resolve: Analyzes the dependency tree and identifies all RPM files required for operation as download targets.
• --alldeps: Forces all dependent packages to be downloaded without omitting them, even if the libraries already exist on the host executing the download.
• --destdir=/tmp/haproxy_rpms: Outputs the downloaded RPMs collectively to the specified directory.

When explicitly acquiring a specific version (e.g., haproxy-2.2.0-1.el8), verify the list of versions in the repository and specify the version string.

# Check available duplicate and older versions
sudo dnf --showduplicates list haproxy

# Explicitly download a specific version
sudo dnf download --destdir=/tmp/haproxy_rpms haproxy-2.2.0-1.el8

Creating and Deploying a Local Repository in an Offline Environment

After transferring the acquired RPMs to the target server in the air-gapped environment via USB flash drive or internal storage, initialize a local filesystem-based DNF repository.

1. Generating Repository Metadata

Navigate to the destination directory and create XML-formatted metadata (repodata) using the createrepo utility.

cd /tmp/haproxy_rpms
sudo createrepo .

2. Configuring the Repository Definition File

Create a .repo configuration file pointing to the local repository under /etc/yum.repos.d/.

cat << EOF | sudo tee /etc/yum.repos.d/haproxy-local.repo
[haproxy-local]
name=HAProxy Local Repository
baseurl=file:///tmp/haproxy_rpms
enabled=1
gpgcheck=0
EOF

3. Executing Installation from the Local Repository

Once configuration is complete, reference the local metadata and execute the installation.

sudo dnf clean all
sudo dnf install -y haproxy

Troubleshooting

Below are representative troubleshooting steps for errors caused by permissions, SELinux, and dependency mismatches during local repository operations and package installations in an offline environment.

1. /tmp Directory Permissions and SELinux Context Denials

When placing a repository under /tmp, metadata read errors may occur due to SELinux access controls or system temporary file cleanup jobs (systemd-tmpfiles).

Example Symptoms:

Error: Failed to download metadata for repo 'haproxy-local': Cannot download repomd.xml: Cannot open file

Workaround: Change the repository location to a persistent directory such as /opt/local_repos/haproxy and reapply the appropriate SELinux context.

sudo mkdir -p /opt/local_repos/haproxy
sudo mv /tmp/haproxy_rpms/* /opt/local_repos/haproxy/
sudo restorecon -Rv /opt/local_repos/haproxy

Rebuild the cache after updating baseurl in /etc/yum.repos.d/haproxy-local.repo to file:///opt/local_repos/haproxy.

2. GPG Signature Verification Error

When gpgcheck=1 is set, the installation will be aborted if the public key has not been imported.

Workaround: For local verification purposes, set gpgcheck=0 or import the official Red Hat GPG key in advance.

sudo rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-redhat-release

3. System Verification Log Protocol

Example terminal verification commands and execution logs to confirm service status and system socket health after deployment completion.

$ sudo systemctl enable --now haproxy
Created symlink /etc/systemd/system/multi-user.target.wants/haproxy.service -> /usr/lib/systemd/system/haproxy.service.

$ sudo systemctl status haproxy
● haproxy.service - HAProxy Load Balancer
   Loaded: loaded (/usr/lib/systemd/system/haproxy.service; enabled; vendor preset: disabled)
   Active: active (running) since Tue 2026-09-01 10:15:30 KST; 12s ago
 Main PID: 14820 (haproxy)
    Tasks: 2 (limit: 23800)
   Memory: 7.4M
   CGroup: /system.slice/haproxy.service
           ├─14820 /usr/sbin/haproxy -Ws -f /etc/haproxy/haproxy.cfg -p /run/haproxy.pid
           └─14822 /usr/sbin/haproxy -Ws -f /etc/haproxy/haproxy.cfg -p /run/haproxy.pid

$ haproxy -v
HA-Proxy version 2.2.9-3.el8 2021/08/10
Configuration file is /etc/haproxy/haproxy.cfg

Configuration Notes

• Ensuring Completeness of Package Dependencies: When executing dnf download --resolve --alldeps in a staging environment, using a node with an OS build version and minimal installation (Minimal Install) equivalent to the target environment as much as possible helps prevent missing dependent libraries.
• Periodic Update of Repository Indexes: Whenever packages are added or replaced, always execute createrepo --update /opt/local_repos/haproxy to recalculate the metadata index.
• Alignment with Security Policies: In production environments, maintaining gpgcheck=1 and automating the checksum comparison and signature verification process for downloaded RPMs is recommended.