Web virtual host refers to running multiple web sites in the same server, each of which does not actually occupy the entire server. Therefore, it is called a “virtual” web host, and the virtual web hosting service can make full use of the server. Hardware resources.
Using httpd makes it easy to set up a virtual host server. It only needs to run an httpd service to support a large number of web sites at the same time. There are three types of virtual hosts supported by httpd (like the Windows IIS service):
A virtual host with the same IP, port number, and different domain name;
Virtual host with the same IP and different port numbers;
Virtual hosts with different IP addresses and the same port number;
Most O&M personnel should adopt the first solution when setting up a virtual host. The virtual host is based on different domain names, which is also the most user-friendly solution.
First, start building a domain-based virtual host:
Provide domain name resolution for virtual hosts
[root@localhost /]
# vim /etc/named.conf
zone “mohan1.com” in {
type master;
file “mohan1.com.zone”;
};
zone “mohan2.com” in {
type master;
file “mohan2.com.zone”;
};
root@localhost /]# vim /var/named/mohan1.com.zone
in ns www.mohan1.com.
www in a 192.168.1.1
[root@localhost /]
# vim /var/named/mohan2.com.zone
in ns www.mohan2.com.
www in a 192.168.1.1
2, prepare web documents for the virtual host
Prepare website directories and web documents for each virtual web host. For the convenience of mohaning, each virtual web host is provided with a different home page file:
[root@localhost named]
# mkdir -p /var/www/mohan1com
[root@localhost named]
# mkdir -p /var/www/mohan2com
[root@localhost named]
# echo “
www.mohan1.com
” > /var/www/mohan1com/index.html
[root@localhost named]
# echo “
www.mohan2.com
” > /var/www/mohan2com/index.html
3, add virtual host configuration
[root@localhost named]
# vim /usr/local/httpd/conf/extra/httpd-vhosts.conf
ServerAdmin admin@mohan.com
DocumentRoot “/var/www/mohan1com”
ServerName www.mohan1.com
ErrorLog “logs/mohan1-error_log”
CustomLog “logs/mohan1-access_log” common
require all granted
mohan2
ServerAdmin admin@mohan.com
DocumentRoot “/var/www/mohan2com”
ServerName www.mohan2.com
ErrorLog “logs/mohan2-error_log”
CustomLog “logs/mohan2-access_log” common
require all granted
[root@localhost named]
# vim /usr/local/httpd/conf/httpd.conf
Include conf/extra/httpd-vhosts.conf
[root@localhost named]
# systemctl restart httpd
Access the virtual web host in the client
Verify it, the result is as follows:
Second, the virtual host based on IP address:
(100,000 don’t want to write down, because the next content can be understood, it won’t be used, but….. Just in case, just write it)
Note that there is no connection between each method. Don’t confuse IP-based virtual hosts with domain-based ones.
[root@localhost named]
# vim /usr/local/httpd/conf/extra/httpd-vhosts.conf
…………..
ServerAdmin admin@mohan.com
DocumentRoot “/var/www/mohan1com”
ErrorLog “mohan1-error_log”
CustomLog “mohan1-access_log” common
require all granted
ServerAdmin admin@mohan.com
DocumentRoot “/var/www/mohan2com”
ErrorLog “mohan2-error_log”
CustomLog “mohan2-access_log” common
require all granted
[root@localhost named]
# vim /usr/local/httpd/conf/httpd.conf
………………….
Include conf/extra/httpd-vhosts.conf
[root@localhost named]
# systemctl restart httpd
Second, the port-based virtual host:
[root@localhost named]
# vim /usr/local/httpd/conf/extra/httpd-vhosts.conf
ServerAdmin admin@mohan.com
DocumentRoot “/var/www/mohan1com”
ErrorLog “mohan1-error_log”
CustomLog “mohan1-access_log” common
require all granted
ServerAdmin admin@mohan.com
DocumentRoot “/var/www/mohan2com”
ErrorLog “mohan2-error_log”
CustomLog “mohan2-access_log” common
require all granted
listen 8000
[root@localhost named]
# vim /usr/local/httpd/conf/httpd.conf
………………….
Include conf/extra/httpd-vhosts.conf
If you frequently access many different remote systems via SSH, this technique will save you some time. You can create SSH aliases for frequently accessed systems via SSH, so you don’t have to remember all the different usernames, hostnames, SSH port numbers, and IP addresses. In addition, it avoids repeatedly entering the same username, hostname, IP address, and port number when SSHing to a Linux server.
Create an SSH alias in Linux
Before I know this trick, I usually use one of the following methods to connect to a remote system via SSH.
Use IP address:
$ ssh 192.168.225.22
Or use the port number, username, and IP address:
$ ssh -p 22 ec2-user@192.168.225.22
Or use the port number, username, and hostname:
$ ssh -p 22 ec2-user@server.example.com
Here
22 is the port number,
ec2-user is the username of the remote system.
192.168.225.22 is the IP of my remote system,
Server.example.com is the host name of the remote system.
I believe that most Linux novices and/or some administrators will connect to remote systems via SSH in this way. However, if you connect to multiple different systems via SSH, remembering all hostnames or IP addresses, as well as usernames, is difficult unless you write them on paper or save them in a text file. do not worry! This can be easily solved by creating an alias (or shortcut) for the SSH connection.
We can create aliases for SSH commands in two ways .
Method 1 – Use an SSH Profile
This is my preferred method of creating an alias.
We can use the SSH default configuration file to create an SSH alias. To do this, edit the ~/.ssh/config file (if this file doesn’t exist, just create one):
$ vi ~/.ssh/config
Add details for all remote hosts as follows:
Host webserver
HostName 192.168.225.22
User ec2-user
Host dns
HostName server.example.com
User root
Host dhcp
HostName 192.168.225.25
User ec2-user
Port 2233
Create an SSH alias in Linux using an SSH configuration file
Replace the values ??of the Host, Hostname, User, and Port configuration with your own values. After adding the details of all remote hosts, save and exit the file.
Now you can access the system via SSH using the following command :
$ ssh webserver
$ ssh dns
$ ssh dhcp
It’s that simple!
Access remote systems using SSH aliases
see it? I only use an alias (such as webserver) to access a remote system with an IP address of 192.168.225.22.
Please note that this is only for the current user. If you want to provide an alias for all users (system-wide), add the above line to the /etc/ssh/ssh_config file.
You can also add a lot of other content to your SSH configuration file. For example, if you have configured SSH key-based authentication, the location of the SSH key file is as follows:
Host Ubuntu
HostName 192.168.225.50
User senthil
IdentityFIle ~/.ssh/id_rsa_remotesystem
Make sure you have replaced your hostname, username, and SSH key file path with your own values.
Now connect to the remote server using the following command:
$ ssh ubuntu
This way, you can add as many remote hosts you want to access via SSH and quickly access them using aliases.
Method 2 – Use a Bash Alias
This is an emergency workaround for creating SSH aliases that speed up communication. You can make this taec2-user easier with the alias command.
Open the ~/.bashrc or ~/.bash_profile file:
Alias ??webserver=’ssh ec2-user@server.example.com’
Alias ??dns=’ssh ec2-user@server.example.com’
Alias ??dhcp=’ssh ec2-user@server.example.com -p 2233′
Alias ??ubuntu=’ssh ec2-user@server.example.com -i ~/.ssh/id_rsa_remotesystem’
Again, make sure you have replaced the host, hostname, port number, and IP address with your own values. Save the file and exit.
Then, use the command to apply the changes:
$ source ~/.bashrc
or
$ source ~/.bash_profile
In this method, you don’t even need to use the ssh alias command. Instead, just use an alias as shown below.
$ webserver
$ dns
$ dhcp
$ ubuntu
NOTE: On Virtual BOX disable NAT network interface before hitting init
or else port 6443 will get bound to NAT IP
disconnect N/A from console and reboot
kubeadm init –pod-network-cidr=10.244.0.0/16
Note: If you have multiple IPs / Hostname to bind ; run following to add name/ip in certificate
You should now deploy a pod network to the cluster.
Run “kubectl apply -f [podnetwork].yaml” with one of the options listed at:
https://kubernetes.io/docs/concepts/cluster-administration/addons/
You can now join any number of machines by running the following on each node
as root:
In order for your pods to communicate with one another, you’ll need to install pod networking. We are going to use Flannel for our Container Network Interface (CNI) because it’s easy to install and reliable. Enter this command:
The connection to the server localhost:8080 was refused – did you specify the right host or port?
Do the following as normal user
su – kubeadmin
sudo cp /etc/kubernetes/admin.conf $HOME/
sudo chown $(id -u):$(id -g) $HOME/admin.conf
export KUBECONFIG=$HOME/admin.conf
[root@kubmaster ~]
# kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
clusterrole.rbac.authorization.k8s.io “flannel” created
clusterrolebinding.rbac.authorization.k8s.io “flannel” created
serviceaccount “flannel” created
configmap “kube-flannel-cfg” created
daemonset.extensions “kube-flannel-ds” created
Ansible role to setup 1 master +2 node kubernetes cluster (more nodes can be added)
setup centos VMs
configure hostnames
Update hosts file template in ../roles/kubernetes-deploy/files/hosts.template with host names and ipaddress
setup password less auth between your Ansible host and Kubernetes nodes
NOTE: On Virtual BOX disable NAT network interface before hitting init
or else port 6443 will get bound to NAT IP
disconnect N/A from console and reboot
kubeadm init –pod-network-cidr=10.244.0.0/16
Note: If you have multiple IPs / Hostname to bind ; run following to add name/ip in certificate
You should now deploy a pod network to the cluster.
Run “kubectl apply -f [podnetwork].yaml” with one of the options listed at:
https://kubernetes.io/docs/concepts/cluster-administration/addons/
You can now join any number of machines by running the following on each node
as root:
In order for your pods to communicate with one another, you’ll need to install pod networking. We are going to use Flannel for our Container Network Interface (CNI) because it’s easy to install and reliable. Enter this command:
The connection to the server localhost:8080 was refused – did you specify the right host or port?
Do the following as normal user
su – kubeadmin
sudo cp /etc/kubernetes/admin.conf $HOME/
sudo chown $(id -u):$(id -g) $HOME/admin.conf
export KUBECONFIG=$HOME/admin.conf
[root@kubmaster ~]
# kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
clusterrole.rbac.authorization.k8s.io “flannel” created
clusterrolebinding.rbac.authorization.k8s.io “flannel” created
serviceaccount “flannel” created
configmap “kube-flannel-cfg” created
daemonset.extensions “kube-flannel-ds” created
ombining other answers, this is what I came up with for bash:
for n in $(kubectl get -o=name pvc,configmap,serviceaccount,secret,ingress,service,deployment,statefulset,hpa,job,cronjob) do mkdir -p $(dirname $n) kubectl get -o=yaml --export $n > $n.yaml done
kubectl get all --export=true -o yaml
!/bin/env bash i=$((0)) for n in $(kubectl get -o=custom-columns=NAMESPACE:.metadata.namespace,KIND:.kind,NAME:.metadata.name pv,pvc,configmap,ingress,service,secret,deployment,statefulset,hpa,job,cronjob --all-namespaces | grep -v 'secrets/default-token') do if (( $i < 1 )); then namespace=$n i=$(($i+1)) if [[ "$namespace" == "PersistentVolume" ]]; then kind=$n i=$(($i+1)) fi elif (( $i < 2 )); then kind=$n i=$(($i+1)) elif (( $i < 3 )); then name=$n i=$((0)) if [[ "$namespace" != "NAMESPACE" ]]; then mkdir -p $namespace yaml=$((kubectl get $kind -o=yaml $name -n $namespace ) 2>/dev/null) if [[ $kind != 'Secret' || $yaml != *"type: kubernetes.io/service-account-token"* ]]; then echo "Saving ${namespace}/${kind}.${name}.yaml" kubectl get $kind -o=yaml --export $name -n $namespace > $namespace/$kind.$name.yaml fi fi fi done
To get the yaml for a deployment (service, pod, secret, etc): kubectl get deploy deploymentname -o yaml --export
kubectl get deployment,service,pod yourapp -o yaml --export Answering @Sinaesthetic question: any idea how to do it for the full cluster (all deployments)? kubectl get deploy --all-namespaces -o yaml --export The problem with this method is that export doesn't include the namespace. So if you want to export many resources at the same time, I recommend doing it per namespace: kubectl get deploy,sts,svc,configmap,secret -n default -o yaml --export > default.yaml Unfortunately kubernetes still doesn't support a true get all command, so you need to list manually the type of resources you want to export. You can get a list of resource types with kubectl api-resources
Amazon EC2 Simple Systems Manager (SSM) is an Amazon Web Services tool that allows us to automatically configure virtual servers in a cloud or in on-premises data center.
We can use scripts, commands or the Elastic Compute Cloud (EC2) console to manage EC2 instances, virtual machines (VMs) or servers hosted on other clouds, or within local environments such as Windows.
Granting user account access to Systems Manager
Our user account must be configured to communicate with the SSM API.
We need to use the following the procedure to attach a managed AWS Identity and Access Management (IAM) policy to our user account that grants us full access to SSM API actions.
In the Filter field, type AmazonSSMFullAccess and press Enter.
Select the check box next to AmazonSSMFullAccess and then choose Policy Actions, Attach.
On the Attach Policy page, choose the user account and then choose Attach Policy.
AWS Identity and Access Management (IAM)
We must configure an AWS Identity and Access Management (IAM) instance profile role for Systems Manager.
The AmazonEC2RoleforSSM role should be attached to an Amazon EC2 instance. Let’s create it first:
Attach the role while the instance is being created:
This role enables the instance to communicate with the Systems Manager API.
Install the SSM Agent (Linux)
The SSM agent processes Run Command requests and configures the instances that are specified in the request. The agent is installed, by default, on Windows instance. However, we must manually install the agent on Linux. The following procedure describes how to install the agent on Ubuntu:
We can use the following steps to list all services running on the instance by using Run Command from the Amazon EC2 console.
To execute a command using Run Command from the EC2 console:
In the navigation pane, choose Run Command:
Choose Run a command:
For Command document, choose AWS-RunPowerShellScript for Windows instances, and AWS-RunShellScript for Linux instances.
For Target instances, choose the instance we created. If we don’t see the instance, verify that we are currently in the same region as the instance we created. Also verify that we configured the IAM role and trust policies as described earlier.
For Commands, type Get-Service for Windows, or ps -aux | less for Linux.
(Optional) For Working Directory, specify a path to the folder on our EC2 instances where we want to run the command.
(Optional) For Execution Timeout, specify the number of seconds the EC2Config service or SSM agent will attempt to run the command before it times out and fails.
For Comment, providing information is recommended so that it will help us identify this command in our list of commands.
For Timeout (seconds), type the number of seconds that Run Command should attempt to reach an instance before it is considered unreachable and the command execution fails.
Choose Run to execute the command. Run Command displays a status screen. Choose View result.
To view the output, choose the command invocation for the command, choose the Output tab.
Then choose View Output.
Sending a Command via AWS CLI
We must either have administrator privileges on the instances we want to configure or we must have been granted the appropriate permission in IAM.
The following command returns a list of Linux and Windows documents:
$ aws ssm list-documents
DOCUMENTIDENTIFIERS Command 1 AWS-ApplyPatchBaseline Amazon 1.2
PLATFORMTYPES Windows
PLATFORMTYPES Linux
DOCUMENTIDENTIFIERS Command 1 AWS-ConfigureAWSPackage Amazon 2.0
PLATFORMTYPES Windows
PLATFORMTYPES Linux
...
To check if an instance is ready to receive commands:
$ aws ssm describe-instance-information --output text --query "InstanceInformationList[*]"
2.0.796.0 ip-172-31-38-206 172.31.38.206 i-0698042a954420857 True 1496457091.34 Online Ubuntu Linux 16.04 EC2Instance
Using Run Command and the AWS-RunShellScript document, we can execute any command or script on an EC2 instance as if we were logged on locally.
To view the description and available parameters, we can use the following command to view a description of the Systems Manager JSON document:
$ aws ssm describe-document --name "AWS-RunShellScript" --query "[Document.Name,Document.Description]"
AWS-RunShellScript Run a shell script or specify the commands to run.
We can use the following command to view the available parameters and details about those parameters:
$ aws ssm describe-document --name "AWS-RunShellScript" --query "Document.Parameters[*]"
(Required) Specify a shell script or a command to run. commands StringList
(Optional) The path to the working directory on your instance. workingDirectory String
3600 (Optional) The time in seconds for a command to complete before it is considered to have failed. Default is 3600 (1 hour). Maximum is 28800 (8 hours). executionTimeout String
We may want to use the following command to get IP information for an instance:
The following command uses the Command ID that was returned from the previous command to get the details and response data of the command execution. The system returns the response data if the command completed. If the command execution shows “Pending” we will need to execute this command again to see the response data:
The following command displays the default user account running the commands:
$ sh_command_id=$(aws ssm send-command --instance-ids "i-0698042a954420857" --document-name "AWS-RunShellScript" --comment "Demo run shell script on Linux Instance" --parameters commands=whoami --output text --query "Command.CommandId")
The following command uses the Command ID to get the status of the command execution on the instance. This example uses the Command ID that was returned in the previous command:
$ aws ssm list-commands --command-id $sh_command_id
COMMANDS 136b1a05-6724-45f1-a23b-f98062fca64d Demo run shell script on Linux Instance 1 AWS-RunShellScript 0 1496465641.83 50 0 1496458441.83 Success Success 1
INSTANCEIDS i-0698042a954420857
NOTIFICATIONCONFIG
COMMANDS whoami
The following command uses the Command ID from the previous command to get the status of the command execution on a per instance basis:
International Men’s Health Week, which is celebrated annually during the week ending on Father’s Day, honours the importance of the health and wellness of boys and men. International Men’s Health Week provides an opportunity to educate the public about what can be done to improve the state of men’s health.
With today’s world becoming full of stress, pressures and health crises, the body faces early depreciation than before. On the occasion of International Men’s Health Week, we take a look at some important health tests men should take to indicate how fit they are and what changes they need to bring about for a healthier life.
Blood Sugar Test: It measures the amount of glucose in the blood and is an important screening for diabetes or pre-diabetes and insulin resistance. Untreated diabetes can cause problems with eyes, feet, heart, skin, nerves, kidneys and more. It can also affect mental health. The risk of prostate and other cancers also increases with high blood sugar.
Colorectal Cancer Screening: Men above 40 should get screened for colon cancer. Any of the three following tests: the sigmoidoscopy, colonoscopy, and the faecal occult blood test can help in detection. A colonoscopy is painless and takes only 15 to 20 minutes. Even better, this test can detect colon cancer early, when it’s most treatable.
Cholesterol test: There are three kinds of cholesterol circulating in the blood. Men above forty should get themselves checked for total cholesterol, low-density lipoprotein (LDL) or bad cholesterol and high-density lipoprotein (HDL) or good cholesterol. High cholesterol is the cause of heart disease.
Bone Density: While osteoporosis may be more common in women, men get it too. According to experts, men over 50 who are in a high-risk group (family history, sedentary lifestyle etc) should get themselves tested. A bone density can determine the strength of a person’s bone and the risk of a fracture.
Testosterone test: With age, there is a risk in a dip in libido as well. Low testosterone can cause erectile dysfunction, fatigue, weight gain, loss of muscle, loss of body hair, sleep problems, trouble concentrating, bone loss, and personality changes.
Stool sample Test: This test helps determine if there are any impurities in the blood and must be done once in every 2 years once you cross 40.
PSA test: The PSA test is a blood test used primarily to screen for prostate cancer. The test measures the amount of prostate-specific antigen (PSA) in your blood.
Eye test: Getting eye tests done post 40 is pertinent as the risk of Hypermetropia or long-sightedness as well as myopia increases with age. Diabetes could also increase the risk of both eye ailments.
In the production environment, Tomcat generates a lot of logs every day. If you don’t clean up the disk capacity, it will be enough. Manual cleaning is too much trouble. Therefore, write a script to delete the log files 5 days ago (depending on the actual situation).
Writing a script
Write a /usr/local/script/cleanTomcatlog.sh script
Set the cleanTomcatlog.sh script to execute
chmod a+x cleanTomcatlog.sh
Enter the following command
crontab -e on the console
Press i to edit this text file, enter the following, restart tomcat every day at 4:30 am
Press esc to exit editing, enter wq and enter to save
30 04 * * * /usr/local/script/cleanTomcatlog.sh
Press esc to exit editing, enter wq and enter to save.
The restart timer task
[the root @]
# the crond STOP-Service [the root @] # the crond Start-Service
Name explanation
Explain the crontab and find commands
Crontab
can set the execution schedule of the program through crontab, for example, let the program execute at 8 o’clock every day, or every 10 o’clock on Monday.
crontab -l lists the schedule;
crontab -e to edit schedule;
crontab -d deletion schedule; “the -l” nothing to say, is a view of it; “-e” is the editor,
and vi no difference (in fact, vi is editing a specific file); “-d” basic need, because it put all the user’s schedule are removed, usually do not put a timetable for progressive deleted with “-e” editor; that How to edit it? crontab file format is: MHD md CMD. A 6 field, the last CMD is the program to be executed, such as cleanTomcatlog.sh. M: minute (0-59) H: hour (0-23) D: date (1-31) m: month (1-12) d: one day of the week (0-6, 0 for Sunday) these five fields separated by a space of time which can be a digital value, may be a plurality of numbers separated by commas (or other), if there were not set,
the default is “*.” For example, every day 04 points 30 points execution cleanTomcatlog.sh, is == 30 04 * * * /usr/local/script/cleanTomcatlog.sh==.
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