Creating CSR with multiple Domains With Openssl

Creating a CSR (Certificate Signing Request) with multiple domains using OpenSSL involves generating a private key and a CSR file, which includes the details of the domain(s) to be included in the certificate. The process involves the following steps:

Generate a private key using the openssl command with the following syntax:

openssl genrsa -out domain.key 2048

This generates a private key file named "domain.key" with 2048 bits of encryption.

Create a configuration file (e.g. domain.conf) that contains the details of the domains to be included in the certificate. This file should contain the following details:

[req]

default_bits       = 2048

default_keyfile    = domain.key

distinguished_name = req_distinguished_name

req_extensions     = req_ext

[req_distinguished_name]

countryName             = Country Name (2 letter code)

stateOrProvinceName     = State or Province Name (full name)

localityName            = Locality Name (eg, city)

organizationName        = Organization Name (eg, company)

commonName              = Common Name (e.g. server FQDN or YOUR name)

emailAddress            = Email Address

[req_ext]

subjectAltName          = @alt_names

[alt_names]

DNS.1                  = example.com

DNS.2                  = www.example.com

DNS.3                  = subdomain.example.com

In the example above, "example.com", "www.example.com", and "subdomain.example.com" are included as the alternate domain names.

Generate a CSR file using the openssl command with the following syntax:

openssl req -new -sha256 -key domain.key -out domain.csr -config domain.conf

This generates a CSR file named "domain.csr" that contains the details of the private key and the alternate domain names specified in the configuration file.

Submit the CSR file to a Certificate Authority (CA) to obtain a signed SSL certificate that can be installed on the server.

Overall, this process allows for the creation of a CSR file with multiple domain names that can be used to obtain a signed SSL certificate to secure those domains.

docker: 'stack' is not a docker command.

The error message "docker: 'stack' is not a docker command" suggests that the version of Docker being used does not support the "stack" command. The solution to this problem is to upgrade Docker to version 1.13 or higher. In the given example, the solution is to upgrade Docker to version 1.13 by downloading the required RPM packages from the Docker project repository and installing them using the "rpm -i" command. After the installation, the "systemctl enable docker" and "systemctl start docker" commands are used to enable and start the Docker service.While deploying the docker services using stack deploy command. We got following error.

docker stack deploy -c docker-compose.yml appslab

docker: 'stack' is not a docker command.
See 'docker --help'.

Resolution
Upgrade docker to 1.13

In Centos 7 we used the following to get the docker upgraded. Now the docket-latest package in centos7 is upgraded to 1.13

wget https://yum.dockerproject.org/repo/main/centos/7/Packages/docker-engine-1.13.1-1.el7.centos.x86_64.rpm
wget https://yum.dockerproject.org/repo/main/centos/7/Packages/docker-engine-selinux-1.13.1-1.el7.centos.noarch.rpm

#package for docker-engine-selinux

yum install -y policycoreutils-python
rpm -i docker-engine-selinux-1.13.1-1.el7.centos.noarch.rpm

#package for docker-engine

yum install -y libtool-ltdl libseccomp
rpm -i docker-engine-1.13.1-1.el7.centos.x86_64.rpm

#remove rpm packages

rm docker-engine-* -f

#enable systemd service

systemctl enable docker

#start docker

systemctl start docker

Fedora 26 + Virtualbox 5.1 + kenel 4.12

Upgrading your virtual machine (VM) environment can sometimes lead to unexpected issues. A common problem users might encounter after upgrading VirtualBox is the VM failing to start. In this post, we'll walk through a specific error and provide a step-by-step guide to resolve it, ensuring your virtual environment gets back up and running smoothly.

Understanding the Error

Upon attempting to start a VM after an upgrade, you might encounter an error in your logs similar to this:

/tmp/vbox.0/r0drv/linux/memuserkernel-r0drv-linux.o: warning: objtool: .fixup: unexpected end of section
if [ "-pg" = "-pg" ]; then if [ /tmp/vbox.0/r0drv/linux/memuserkernel-r0drv-linux.o != "scripts/mod/empty.o" ]; then ./scripts/recordmcount "/tmp/vbox.0/r0drv/linux/memuserkernel-r0drv-linux.o"; fi; fi;
make[1]: *** [Makefile:1519: _module_/tmp/vbox.0] Error 2
make: *** [Makefile:304: vboxdrv] Error 2

This error typically indicates a problem with the VirtualBox kernel modules not compiling or loading correctly due to incompatibilities or issues within the system.

Step-by-Step Solution

Fear not, as this issue can often be resolved by applying a patch to the VirtualBox source. Here's how you can fix it:

1. Change to the VirtualBox Source Directory:

Navigate to the directory where VirtualBox sources are stored:

cd /usr/share/virtualbox/src

2. Obtain the Necessary Patch:

Download the patch designed to fix the issue:

sudo wget http://paste.siduction.org/20170629003423

3. Apply the Patch:

Apply the downloaded patch to the VirtualBox source:

sudo patch -Np0 < 20170629003423

4. Reconfigure VirtualBox:

After applying the patch, you need to reconfigure VirtualBox to make sure it recognizes the changes:

/sbin/vboxconfig

Post-Solution Tips:

Have Fun! Now that you've resolved the issue, your VMs should start as expected. Dive back into your virtual environment and continue your work or play.

Stay Updated: Keep your system and VirtualBox updated to avoid similar issues in the future. Developers regularly release patches and updates to address known bugs and compatibility issues.

Seek Community Help: If you encounter further issues or the problem persists, don't hesitate to seek help from the VirtualBox community forums or check out other user experiences for additional insights.

Conclusion

Encountering errors after a system or software upgrade can be frustrating, but with the right approach and resources, most issues can be resolved. By understanding the error, carefully following the provided steps, and engaging with the community, you can overcome challenges and enjoy a seamless virtualization experience with VirtualBox. Keep exploring, learning, and sharing your knowledge with others!