What information contains in a certificate?

Certificate is normally issued to an individual or a company by CA. In cryptography, a public key certificate, also known as a digital certificate or identity certificate, is an electronic document used to prove the ownership of a public key. Which contains the following information.

openssl x509 -in tlsca.org2msp-cert.pem -text -noout

Certificate:
    Data:
        Version: 3 (0x2)
        Serial Number:
            df:c6:71:a4:bb:41:1f:73:83:ed:d5:95:93:24:2f:f6
    Signature Algorithm: ecdsa-with-SHA256
        Issuer: C=US, ST=California, L=San Francisco, O=org2msp, CN=tlsca.org2msp
        Validity
            Not Before: Feb 20 17:20:00 2019 GMT
            Not After : Feb 17 17:20:00 2029 GMT
        Subject: C=US, ST=California, L=San Francisco, O=org2msp, CN=tlsca.org2msp
        Subject Public Key Info:
            Public Key Algorithm: id-ecPublicKey
                Public-Key: (256 bit)
                pub:
                    04:02:ea:14:c2:52:0d:02:10:02:c1:6e:41:8e:b7:
                    33:0e:73:4b:1f:9d:8a:b3:d0:90:41:2d:4f:49:4f:
                    ee:cf:20:05:d4:e6:26:99:d4:d4:90:1c:71:02:bc:
                    1f:30:15:b1:b2:d4:b2:49:d5:9f:7b:f8:20:15:e6:
                    cc:ae:75:05:12
                ASN1 OID: prime256v1
                NIST CURVE: P-256
        X509v3 extensions:
            X509v3 Key Usage: critical
                Digital Signature, Key Encipherment, Certificate Sign, CRL Sign
            X509v3 Extended Key Usage:
                TLS Web Client Authentication, TLS Web Server Authentication
            X509v3 Basic Constraints: critical
                CA:TRUE
            X509v3 Subject Key Identifier:
                1A:23:57:FF:C1:BC:12:26:EA:94:44:2A:35:E6:A6:AA:9A:58:26:B1:03:52:04:44:10:DA:54:AA:08:2D:D5:5D
    Signature Algorithm: ecdsa-with-SHA256
         30:44:02:20:68:f1:1c:b3:25:ac:a8:99:31:f1:a9:c5:ce:51:
         c6:cc:90:2f:06:1e:d0:8c:51:e3:1c:f6:30:3d:dd:59:49:8e:
         02:20:1b:88:49:b2:ce:c8:1e:30:52:d1:25:a7:7a:47:ff:a4:
         03:1b:8d:e5:48:4e:6a:e9:2d:eb:07:36:d3:b5:c0:d4

Install perf on fabric container

1. apt install linux-tools-generic
2. apt install linux-tools-4.4.0-141-generic

dstat
apt install dstat

dstat -cd --disk-util --disk-tps

apt install atop ioping

iotop
lsblk

ioping /dev/xvdc

Resize VirtualBox Hard disk

After your virtual machine run for awhile, you found that your originally allocated virtual hard disk may run out of the space. You may not always want to recreate the vm since you may have things in the VM that you do not want to destroy. Here is the process to size the hard disk without destroy what is already in the VM.

1. Use VBoxManage modifyhd command:

   VBoxManage modifyhd NGINX.vdi --resize 30000

  The parameter for --resize is in MB. 30000 is 30GB. 40000 is 40GB.

2. If your VM has snapshots, you will have to do the exact same command for each snapshot vdi file. Without doing this, you will not be able to do the next step.

3. Use gparted iso mounted onto your VM and then boot up your VM.
4. Use the gparted to resize your disk, then reboot your VM. Your VM at this point will have resized disk size.