these were the commands I used during troubleshooting

sshpass -p '******' ssh -o StrictHostKeyChecking=no loki@172.16.238.14 systemctl status haproxy ls -l /usr/lib/systemd/system | grep haprox sudo systemctl restart haproxy cat /usr/lib/systemd/system/haproxy.service sudo vi /usr/lib/systemd/system/haproxy.service systemctl daemon-reload haproxy -c -f /etc/haproxy/haproxy.cfg

these were the commands I used to finish the lab

1. Connect to the LBR server

This was actually the first time that I connected to this server.

sshpass -p '******' ssh -o StrictHostKeyChecking=no loki@172.16.238.14

2. Check status of haproxy service. Verify also if config file is valid.

Status shows 'dead' so I restarted it and checked status again.

Status shows more information after restarting service.

systemctl status haproxy sudo systemctl restart haproxy systemctl status haproxy

So as an additional step, I checked the content for the haproxy.service file

before I checked the haproxy.cfg config file.

cat /usr/lib/systemd/system/haproxy.service cat /etc/haproxy/haproxy.cfg

Then I verified if config file is valid.

Now this one, I don't really have a clue of this.

I just found this on one article from KKC.

I read the whole forum of course, but this is definitely the first time I

saw this kind of issue and ofcourse, this command.

haproxy -c -f /etc/haproxy/haproxy.cfg # checks config file

3. Modify config file - change any incorrect part.

Now this is the part where it all gets tricky. As one KKC article suggests,

there's just a typo error on the config file. The article suggests finding the

'checking' and then changing it to 'check'

I found that, changed it, resarted the service and then verified it's working.

Believing this was the final solution, I hit 'Try again' and redo the steps again

up to config file.

And voila, there was no typo error and 'check' was in there.

So I t-shooted for a bit and returned to the config file and read it again.

Issued again this command to see if it will show another information

haproxy -c -f /etc/haproxy/haproxy.cfg

And lo and behold, it says it can't find the backend app or something.

So I went back to the config file, found the section, and indeed the line that

should describe the app was COMMENTED.

So I removed the comment.

sudo vi /etc/haproxy/haproxy.cfg

4. Restart service and then verify.

After uncommenting that particular line, I restarted the service and checked the status,

And yes, it's now showing as 'RUNNING'

sudo systemctl restart haproxy systemctl status haproxy

So as always, there's suppose to be some way other than the status to verify if everything

is working as they should. So I issued this command again.

Luckily, it now shows 'CONFIGURATION FILE IS VALID'

haproxy -c -f /etc/haproxy/haproxy.cfg

IV. STEPS - BREAKDOWN

So this one lies somewhere between 'RIGHT ON' and 'QUITE HARD'

But I guess it's much better to say taht it was tricky.

This lab took me around 3 or 4 attempts and it took more time that I expected.

I did a couple of t-chooting on my own before caving in to check the KKC.

And as mentioned in the section above, there were two errors that I encountered here.

thor@jump_host /$thor@jump_host /$ sshpass -p '******' ssh -o StrictHostKeyChecking=no loki@172.16.238.14 Warning: Permanently added '172.16.238.14' (ECDSA) to the list of known hosts. [loki@stlb01 ~]$ [loki@stlb01 ~]$ systemctl status haproxy ● haproxy.service - HAProxy Load Balancer Loaded: loaded (/usr/lib/systemd/system/haproxy.service; disabled; vendor preset: disabled) Active: inactive (dead) [loki@stlb01 ~]$ [loki@stlb01 ~]$ sudo systemctl restart haproxy

We trust you have received the usual lecture from the local System Administrator. It usually boils down to these three things:

#1) Respect the privacy of others. #2) Think before you type. #3) With great power comes great responsibility.

[sudo] password for loki: Sorry, try again. [sudo] password for loki: [loki@stlb01 ~]$ systemctl status haproxy ● haproxy.service - HAProxy Load Balancer Loaded: loaded (/usr/lib/systemd/system/haproxy.service; disabled; vendor preset: disabled) Active: failed (Result: exit-code) since Wed 2020-07-22 16:26:28 UTC; 7s ago Process: 91 ExecStart=/usr/sbin/haproxy-systemd-wrapper -f /etc/haproxy/haproxy.cfg -p /run/haproxy.pid $OPTIONS (code=exited, status=1/FAILURE) Main PID: 91 (code=exited, status=1/FAILURE)

Jul 22 16:26:28 stlb01 systemd[91]: Executing: /usr/sbin/haproxy-systemd-wrapper -f /etc/h...pid Jul 22 16:26:28 stlb01 haproxy-systemd-wrapper[91]: [ALERT] 203/162628 (92) : Proxy 'main':... Jul 22 16:26:28 stlb01 haproxy-systemd-wrapper[91]: [ALERT] 203/162628 (92) : Fatal errors ...n. Jul 22 16:26:28 stlb01 haproxy-systemd-wrapper[91]: haproxy-systemd-wrapper: exit, haproxy RC=1 Jul 22 16:26:28 stlb01 systemd[1]: Child 91 belongs to haproxy.service Jul 22 16:26:28 stlb01 systemd[1]: haproxy.service: main process exited, code=exited, sta...LURE Jul 22 16:26:28 stlb01 systemd[1]: haproxy.service changed running -> failed Jul 22 16:26:28 stlb01 systemd[1]: Unit haproxy.service entered failed state. Jul 22 16:26:28 stlb01 systemd[1]: haproxy.service failed. Jul 22 16:26:28 stlb01 systemd[1]: haproxy.service: cgroup is empty Hint: Some lines were ellipsized, use -l to show in full. [loki@stlb01 ~]$ [loki@stlb01 ~]$ haproxy -c -f /etc/haproxy/haproxy.cfg [ALERT] 203/162654 (94) : Proxy 'main': unable to find required default_backend: 'app'. [ALERT] 203/162654 (94) : Fatal errors found in configuration. [loki@stlb01 ~]$ cat /usr/lib/systemd/system/haproxy.service [Unit] Description=HAProxy Load Balancer After=syslog.target network.target

[Service] EnvironmentFile=/etc/sysconfig/haproxy ExecStart=/usr/sbin/haproxy-systemd-wrapper -f /etc/haproxy/haproxy.cfg -p /run/haproxy.pid $OPTIONS ExecReload=/bin/kill -USR2 $MAINPID KillMode=mixed

[Install] WantedBy=multi-user.target [loki@stlb01 ~]$ cat /etc/haproxy/haproxy.cfg #---------------------------------------------------------------------

Example configuration for a possible web application. See the

full configuration options online.

http://haproxy.1wt.eu/download/1.4/doc/configuration.txt

#---------------------------------------------------------------------

Global settings

#--------------------------------------------------------------------- global

to have these messages end up in /var/log/haproxy.log you will

need to:

1) configure syslog to accept network log events. This is done

by adding the '-r' option to the SYSLOGD_OPTIONS in

/etc/sysconfig/syslog

2) configure local2 events to go to the /var/log/haproxy.log

file. A line like the following can be added to

/etc/sysconfig/syslog

local2.* /var/log/haproxy.log

log 127.0.0.1 local2

chroot /var/lib/haproxy pidfile /var/run/haproxy.pid maxconn 4000 user haproxy group haproxy daemon

turn on stats unix socket

stats socket /var/lib/haproxy/stats

#---------------------------------------------------------------------

common defaults that all the 'listen' and 'backend' sections will

use if not designated in their block

#--------------------------------------------------------------------- defaults mode http log global option httplog option dontlognull option http-server-close option forwardfor except 127.0.0.0/8 option redispatch retries 3 timeout http-request 10s timeout queue 1m timeout connect 10s timeout client 1m timeout server 1m timeout http-keep-alive 10s timeout check 10s maxconn 3000

#---------------------------------------------------------------------

main frontend which proxys to the backends

#--------------------------------------------------------------------- frontend main *:5000 acl url_static path_beg -i /static /images /javascript /stylesheets acl url_static path_end -i .jpg .gif .png .css .js

use_backend static if url_static default_backend app

#---------------------------------------------------------------------

static backend for serving up images, stylesheets and such

#--------------------------------------------------------------------- backend static balance roundrobin server static 127.0.0.1:4331 check

#---------------------------------------------------------------------

round robin balancing between the various backends

#--------------------------------------------------------------------- #backend app balance roundrobin server app1 127.0.0.1:5001 check server app2 127.0.0.1:5002 check server app3 127.0.0.1:5003 check server app4 127.0.0.1:5004 check

[loki@stlb01 ~]$ [loki@stlb01 ~]$ sudo vi /etc/haproxy/haproxy.cfg [loki@stlb01 ~]$ [loki@stlb01 ~]$ sudo systemctl restart haproxy [loki@stlb01 ~]$ [loki@stlb01 ~]$ systemctl status haproxy ● haproxy.service - HAProxy Load Balancer Loaded: loaded (/usr/lib/systemd/system/haproxy.service; disabled; vendor preset: disabled) Active: active (running) since Wed 2020-07-22 16:29:40 UTC; 12s ago Main PID: 103 (haproxy-systemd) CGroup: /docker/d49cf7172d89e6a56c8bd6410f9e7d57aa40ff58316736ccf08849e1eedae93e/system.slice/haproxy.service ├─103 /usr/sbin/haproxy-systemd-wrapper -f /etc/haproxy/haproxy.cfg -p /run/haprox... ├─104 /usr/sbin/haproxy -f /etc/haproxy/haproxy.cfg -p /run/haproxy.pid -Ds └─105 /usr/sbin/haproxy -f /etc/haproxy/haproxy.cfg -p /run/haproxy.pid -Ds

Jul 22 16:29:40 stlb01 systemd[1]: Enqueued job haproxy.service/restart as 162 Jul 22 16:29:40 stlb01 systemd[1]: Job haproxy.service/restart finished, result=done Jul 22 16:29:40 stlb01 systemd[1]: Converting job haproxy.service/restart -> haproxy.serv...tart Jul 22 16:29:40 stlb01 systemd[1]: About to execute: /usr/sbin/haproxy-systemd-wrapper -f...IONS Jul 22 16:29:40 stlb01 systemd[1]: Forked /usr/sbin/haproxy-systemd-wrapper as 103 Jul 22 16:29:40 stlb01 systemd[1]: haproxy.service changed failed -> running Jul 22 16:29:40 stlb01 systemd[1]: Job haproxy.service/start finished, result=done Jul 22 16:29:40 stlb01 systemd[1]: Started HAProxy Load Balancer. Jul 22 16:29:40 stlb01 systemd[103]: Executing: /usr/sbin/haproxy-systemd-wrapper -f /etc/...pid Jul 22 16:29:40 stlb01 haproxy-systemd-wrapper[103]: haproxy-systemd-wrapper: executing /us...Ds Hint: Some lines were ellipsized, use -l to show in full. [loki@stlb01 ~]$ [loki@stlb01 ~]$ curl 172.16.238.10:8080 curl: (7) Failed connect to 172.16.238.10:8080; Connection refused [loki@stlb01 ~]$ [loki@stlb01 ~]$ ss nltp Error: an inet prefix is expected rather than "nltp". Cannot parse dst/src address. [loki@stlb01 ~]$ [loki@stlb01 ~]$ ss -nltp State Recv-Q Send-Q Local Address:Port Peer Address:Port LISTEN 0 128 *:22 : LISTEN 0 128 127.0.0.11:34487 : LISTEN 0 128 :5000 : LISTEN 0 128 [::]:22 [::]: [loki@stlb01 ~]$ [loki@stlb01 ~]$ haproxy -c -f /etc/haproxy/haproxy.cfg Configuration file is valid [loki@stlb01 ~]$ [loki@stlb01 ~]$ Connection to host01 closed by remote host. Connection to host01 closed.

The environment has expired.

Please refresh to get a new environment.

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these were the commands I used to finish the lab

1. Connect to the LBR server

This was actually the first time that I connected to this server.

2. Check status of haproxy service. Verify also if config file is valid.

Status shows 'dead' so I restarted it and checked status again.

Status shows more information after restarting service.

So as an additional step, I checked the content for the haproxy.service file

before I checked the haproxy.cfg config file.

Then I verified if config file is valid.

Now this one, I don't really have a clue of this.

I just found this on one article from KKC.

I read the whole forum of course, but this is definitely the first time I

saw this kind of issue and ofcourse, this command.

3. Modify config file - change any incorrect part.

Now this is the part where it all gets tricky. As one KKC article suggests,

there's just a typo error on the config file. The article suggests finding the

'checking' and then changing it to 'check'

I found that, changed it, resarted the service and then verified it's working.

Believing this was the final solution, I hit 'Try again' and redo the steps again

up to config file.

And voila, there was no typo error and 'check' was in there.

So I t-shooted for a bit and returned to the config file and read it again.

Issued again this command to see if it will show another information

And lo and behold, it says it can't find the backend app or something.

So I went back to the config file, found the section, and indeed the line that

should describe the app was COMMENTED.

So I removed the comment.

4. Restart service and then verify.

After uncommenting that particular line, I restarted the service and checked the status,

And yes, it's now showing as 'RUNNING'

So as always, there's suppose to be some way other than the status to verify if everything

is working as they should. So I issued this command again.

Luckily, it now shows 'CONFIGURATION FILE IS VALID'

So this one lies somewhere between 'RIGHT ON' and 'QUITE HARD'

But I guess it's much better to say taht it was tricky.

This lab took me around 3 or 4 attempts and it took more time that I expected.

I did a couple of t-chooting on my own before caving in to check the KKC.

And as mentioned in the section above, there were two errors that I encountered here.

Example configuration for a possible web application. See the

full configuration options online.

http://haproxy.1wt.eu/download/1.4/doc/configuration.txt

Global settings

to have these messages end up in /var/log/haproxy.log you will

need to:

1) configure syslog to accept network log events. This is done

by adding the '-r' option to the SYSLOGD_OPTIONS in

/etc/sysconfig/syslog

2) configure local2 events to go to the /var/log/haproxy.log

file. A line like the following can be added to

/etc/sysconfig/syslog

local2.* /var/log/haproxy.log

turn on stats unix socket

common defaults that all the 'listen' and 'backend' sections will

use if not designated in their block

main frontend which proxys to the backends

static backend for serving up images, stylesheets and such

round robin balancing between the various backends

#### ### ### #### #### #### #### ######### #### #### #### #### ###​

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